[SRU] Update walinuxagent to 2.1.5

[Jose L. VG]

[Impact]

Version 2.1.5 introduced goal state processing extension, multi-nic improvements & several bug fixes: https://github.com/Azure/WALinuxAgent/releases

[Test case 1]: Upgrade testing
1.) Launch instance on Azure
2.) Upgrade walinuxagent from -proposed
3.) Confirm that "waagent" is running, check /var/log/waagent.log
4.) Reboot, repeat step 3
5.) Capture instance and provsion new instances; repeat step 3

[Test Case 2]: New instance
1.) Build new cloud image from -proposed
2.) Boot instance
3.) Confirm that instance provisioned

[Upstream Testing]
The Canonical Cloud Image team has been working with Microsoft to ensure that this package is well tested. Validation will be performed by both Microsoft and the Canonical Cloud Image team.

[Regression Potential]
Currently, WALinuxAgent uses Python 2. With the 2.1.x branch, WALinuxAgent started using Python 3.

This version has been in use on yakkety since release, so it is known to work. Azure consider Ubuntu to be a flagship platform, so will be active in addressing any regressions that are found.

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "lp-1604423.debdiff" seems to be a debdiff. The ubuntu-sponsors team has been subscribed to the bug report so that they can review and hopefully sponsor the debdiff. If the attachment isn't a patch, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are member of the ~ubuntu-sponsors, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issue please contact him.]

[Jose L. VG (josvaz)]

Patch diff against the wrong version (I generated from yakkety package)

This is the debdiff from xenial, and again has been tested from a PPA using both given regression cases.