Adjusted audit logging for taskmanager module

The taskmanager module audit log messages are unclear, some debug
messages are supposed to be info and vice versa.

Changed logging of various messages to conform to standard.

Change-Id: Idaa46b67096c1fbbacdf730c06c823aaf3e1e255
Partial-Bug: #1324206
Update 'list_users' call to use AGENT_HIGH_TIMEOUT

The list_users call in the guestagent takes about 0.4s - 0.5s per
user, and currently uses the AGENT_LOW_TIMEOUT. This means that it's
possible for the call to easily time out if there are ~11-12 users
on the guest.

This has been causing a lot of false negative failures in the
int-tests, so this updates the 'list_users' call to use the
AGENT_HIGH_TIMEOUT instead of the AGENT_LOW_TIMEOUT.

Closes-bug: 1356085
Change-Id: I589baa0e95febfb63538b79a082cc3dc55f66510
Merge "Adjusted audit logging for taskmanager module"
Merge remote-tracking branch 'upstream/master' into stable/juno

Conflicts:
	trove/taskmanager/models.py
Merge branch 'stable/juno' of https://github.com/tesora/tesora-trove into stable/juno