Logging audit for trove/guestagent module

Adjust logging to conform to logging standards. Found
and fixed a pattern of not logging exception information.
Cleaned up some messages that were unclear.

Also addressed a pattern of having exception's using
LOG.error to log the exception (rather than using
LOG.exception).

Change-Id: Idab510051321f4f9ed096c9972322530028ad2e6
Partial-Bug: #1324206
Remove accounts use of non-existent Nova extension

The accounts mgmt extension uses a Nova accounts extension that doesn't
exist. This removes the use of Nova accounts and instead shows all
trove instance ids associated with the account. Accounts index is unchanged
and returns the total number of instances per account for all accounts.

Change-Id: I8a4387aec2e124dfbfb5c55a62fe4154e5e38544
Closes-Bug: 1130924
Merge "Logging audit for trove/guestagent module"
Merge "Remove accounts use of non-existent Nova extension"