Fix KeyError in iproute pformat

[zykovd]

Fix KeyError in iproute pformat

This fixes KeyError on specific network configuration when running cloud-init on "network" stage. The same problem was mentioned in #746 and #1041.

summary: Fix KeyError in iproute pformat

This fixes KeyError on specific network configuration when 
running cloud-init on "network" stage. 

failed run of stage init
------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/cloudinit/cmd/main.py", line 767, in status_wrapper
    ret = functor(name, args)
  File "/usr/lib/python3/dist-packages/cloudinit/cmd/main.py", line 367, in main_init
    sys.stderr.write("%s\n" % (netinfo.debug_info()))
  File "/usr/lib/python3/dist-packages/cloudinit/netinfo.py", line 650, in debug_info
    route_lines = route_pformat().splitlines()
  File "/usr/lib/python3/dist-packages/cloudinit/netinfo.py", line 630, in route_pformat
    r["gateway"],
KeyError: 'gateway'
------------------------------------------------------------

Test Steps

1. Create machine with custom default IPv6 route, i.e.

root@host:~# ip -o -6 route list table all
...                   
default dev eth1 proto static metric 50 pref medium 
...

2. Run cloud-init init

Checklist:

• My code follows the process laid out in the documentation
• I have updated or added any unit tests accordingly
• I have updated or added any documentation accordingly

[TheRealFalcon]

Thanks for the contribution, @zykovd ! I left small comments inline, but overall this change looks good.

I noticed you added yourself to the CLA signers file, but have you signed the actual CLA too? I'm not seeing your information there. If you did, can you provide the date that you signed it?

[TheRealFalcon]

Let's use KeyError here instead of Exception

[zykovd]

Fixed

[TheRealFalcon]

Same comment here

[zykovd]

Fixed

[zykovd]

Thanks for the contribution, @zykovd ! I left small comments inline, but overall this change looks good.

I noticed you added yourself to the CLA signers file, but have you signed the actual CLA too? I'm not seeing your information there. If you did, can you provide the date that you signed it?

I signed the CLA today, 05/11/2023

[TheRealFalcon]

LGTM! Thanks!