Port agent API to v3 Part 2

This patch contains the changes required to adapt the agent
extension and the corresponding unittest to the v3 framework

Partially implements: bp v3-api-extension-versioning

Change-Id: I6baa379ede41a1627f69d5d1a719cf2c6d7e9d9e
Fix and gate on E125

E125 continuation line does not distinguish itself from next logical
line.

E125 makes code more readable, and fixing all the existing issues allows
us to gate on this, making this one less thing reviewers have to check
for.

Fix was made using https://github.com/hhatto/autopep8

Change-Id: Ie569fd74fb84d220ceb87e37b1b1f39143bba80f
Merge "Port agent API to v3 Part 2"
Merge "Fix and gate on E125"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp