add osmajorrelease grain for raspbian

[Ch3LL]

What does this PR do?

Adds the osmajorrelease grains for raspberry pi boxes.

What issues does this PR fix or reference?

Fixes #34321

Previous Behavior

salt '*' grains.item osmajorrelease

raspberrypi:
    ----------
    osmajorrelease

New Behavior

root@raspberrypi:/etc# salt '*' grains.item osmajorrelease
raspberrypi:
    ----------
    osmajorrelease:
        8

Tests written?

Yes

[Ch3LL]

It looks like osmajorrlease is not available for Ubuntu. Is that by design?

[rallytime]

@Ch3LL The osmajorrelease grain is largely used for RHEL-based systems. It looks like Debain supports it now since the 2015.5.0 release (see #15461), but it is not supported for Ubuntu.

This is related to this feature request: #9613

Edit: to answer your question, I don't think that is by design. Just not implemented currently. Unless @cachedout knows why osmajorrelease isn't supported on ubuntu.

[rallytime]

Also, there's a pylint error here: https://jenkins.saltstack.com/job/PR/job/salt-pr-lint-n/2925/violations/file/tests/integration/modules/grains.py/

[Ch3LL]

@rallytime okay I added osmajorrelease to ubuntu and tested with ubuntu14 as well. If you want me to remove osmajorrelease @cachedout let me know and I can go ahead and do that as well. I also fixed the pylint.