fix snap stable & edge release errors

[casperdcl]

• master/edge: fix SNAP_CHANNEL env var automatically being picked up the provider: snap and used incorrectly https://travis-ci.com/iterative/dvc/jobs/278042607#L2168
  • really it should be automatically picked up and used correctly: https://docs.travis-ci.com/user/deployment-v2/providers/snap/#environment-variables. Looks like a travis bug.
• tag/stable: fix version mismatch tag https://travis-ci.com/iterative/dvc/jobs/277748053#L2143
  • dvc --version => <tag>+<hash>.mod rather than <tag>
  • because of making tweaks to source while building the snap package? https://github.com/iterative/dvc/blob/aa86eab2cc4acbfc34279312eaa5cf1b8f30558e/snap/snapcraft.yaml#L30-L33
• continues minor comments #3173, major deploy tidy #3158 <- (re) fixes Snap stable channel not updating #3152
• continues add snap tests #2956 <- (re) fixes add snap tests #2954

[casperdcl]

@efiop any idea what's the best way to avoid the custom --version logic of dvc?

[efiop]

@casperdcl Maybe by simply replacing dvc/version.py with a new file with __version__ = _BASE_VERSION or something like that, if you are not able to comply with the existing logic in the package.

[efiop]

@casperdcl here is how we do it in setup.py https://github.com/iterative/dvc/blob/master/setup.py#L33 , but maybe you could simply install it as a python package inside snap? Sorry, still a bit confused how snap installs stuff internally.

[codecov]

Codecov Report

Merging #3209 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3209   +/-   ##
=======================================
  Coverage   91.66%   91.66%           
=======================================
  Files         139      139           
  Lines        8667     8667           
=======================================
  Hits         7945     7945           
  Misses        722      722

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[casperdcl]

@efiop think this is finally fixed & mergeable

[efiop]

Thanks!

[efiop]

@casperdcl Still failing https://travis-ci.com/iterative/dvc/jobs/278217133#L2170 🙁