Set default_flow_style=None in yaml.dump calls

[Ch3LL]

What does this PR do?

In PyYaml 5.1 they changed the default_flow_style from None to False. Changing this back to None in salt since this is a breaking change to keep backwards compatibility. Here is the PR/commit that added this: yaml/pyyaml#256 yaml/pyyaml@507a464

Would appreciate any further review as I'm not sure if we want to keep backwards compatibility or update salt to ensure default_flow_style=False works properly. But I think this is the least obtrusive change for now.

What issues does this PR fix or reference?

Fixes up some tests on Fedora which has PyYaml 5.1 installed:

#52930
#52929
#52928
#52927

PyYAML 5.1:

>>> test = {'foo': 'bar'}
>>> yaml.dump(test)
'foo: bar\n'

PyYAML 3.13:

>>> test = {'food': 'bar'}
>>> yaml.dump(test)
'{food: bar}\n'

With this change it will always dump like so:

PyYAML 5.1:

>>> yaml.dump(test, default_flow_style=None)
'{food: bar}\n'

PyYAML 3.13:

>>> yaml.dump(test, default_flow_style=None)
'{food: bar}\n'

Tests written?

Yes

Commits signed with GPG?

Yes

[Ch3LL]

started a full test run:

https://jenkinsci.saltstack.com/job/2019.2.1/job/ch3ll-yaml-salt-fedora-29-py2/
https://jenkinsci.saltstack.com/job/2019.2.1/job/ch3ll-yaml-salt-fedora-29-py3/

[waynew]

I bet there's a unicode issue on py3. When we're using pytest this assertion style will actually give us information 😄 Of course, right now... 😢

You're probably aware of both these options, but you could do
self.assertEqual(salt.utils.yamldumper.dump(data), '{!!python/unicode \'foo\': !!python/unicode \'bar\'}\n') for now. Or you could do

actual = salt.utils.yamldumper.dump(data)
assert actual == '{!!python/unicode \'foo\': !!python/unicode \'bar\'}\n', actual

to see what the actual text is.

[Ch3LL]

i'm fine with just sticking to just assert. I know we do not get more information, but this will make it an easier transition to pytest and will get more information then.

[codecov]

Codecov Report

Merging #52957 into 2019.2.1 will increase coverage by 7.54%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##           2019.2.1   #52957      +/-   ##
============================================
+ Coverage     28.78%   36.32%   +7.54%     
============================================
  Files          1563     1576      +13     
  Lines        267054   269470    +2416     
  Branches      57953    56051    -1902     
============================================
+ Hits          76862    97896   +21034     
+ Misses       189762   160525   -29237     
- Partials        430    11049   +10619

Flag	Coverage Δ
#arch	?
#centos7	?
#fedora29	36.32% <100%> (?)
#proxy	?
#py2	36.32% <100%> (+7.63%)	⬆️
#py3	?
#ubuntu1604	?

Impacted Files	Coverage Δ
salt/utils/yamldumper.py	86.27% <100%> (+10.76%)	⬆️
salt/serializers/yaml.py	77.38% <100%> (+7.5%)	⬆️
salt/serializers/yamlex.py	75% <100%> (+64.71%)	⬆️
salt/transport/frame.py	27.27% <0%> (-51.52%)	⬇️
salt/ext/ssl_match_hostname.py	0% <0%> (-36.18%)	⬇️
salt/output/virt_query.py	12.9% <0%> (-35.49%)	⬇️
salt/utils/stringio.py	52.38% <0%> (-33.34%)	⬇️
salt/modules/pdbedit.py	18.33% <0%> (-31.67%)	⬇️
salt/utils/pkg/deb.py	31.57% <0%> (-31.58%)	⬇️
salt/modules/pacmanpkg.py	25% <0%> (-31.44%)	⬇️
... and 1538 more

---

Continue to review full report at Codecov.

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[codecov]

Codecov Report

Merging #52957 into 2019.2.1 will increase coverage by 6.88%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##           2019.2.1   #52957      +/-   ##
============================================
+ Coverage     29.78%   36.66%   +6.88%     
============================================
  Files          1574     1577       +3     
  Lines        269397   269540     +143     
  Branches      58069    57477     -592     
============================================
+ Hits          80227    98832   +18605     
+ Misses       188741   159768   -28973     
- Partials        429    10940   +10511

Flag	Coverage Δ
#arch	?
#centos7	?
#fedora29	36.66% <100%> (?)
#proxy	?
#py2	36.32% <100%> (+6.63%)	⬆️
#py3	35.88% <100%> (+26.12%)	⬆️
#ubuntu1604	?

Impacted Files	Coverage Δ
salt/utils/yamldumper.py	86.27% <100%> (+10.76%)	⬆️
salt/serializers/yaml.py	78.57% <100%> (+8.69%)	⬆️
salt/serializers/yamlex.py	78.97% <100%> (+68.69%)	⬆️
salt/ext/ssl_match_hostname.py	0% <0%> (-36.18%)	⬇️
salt/output/virt_query.py	12.9% <0%> (-35.49%)	⬇️
salt/modules/pdbedit.py	18.33% <0%> (-31.67%)	⬇️
salt/utils/pkg/deb.py	31.57% <0%> (-31.58%)	⬇️
salt/modules/pacmanpkg.py	25% <0%> (-31.44%)	⬇️
salt/runners/bgp.py	21.48% <0%> (-31.41%)	⬇️
salt/modules/bcache.py	8.5% <0%> (-31.33%)	⬇️
... and 1518 more

---

Continue to review full report at Codecov.

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Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f410346...5f6581a. Read the comment docs.