fixing the flags for guest on resize volume

Change-Id: Ic46a307540f284f8824537493d0aaa98a94a6f82
Closes-Bug: #1379908
cluster_config argument missing in prepare()

Due to a bad merge, the prepare() call in postgresql does
not have cluster_config argument. Added that to make sure
postgres is in line with other data stores.

Change-Id: I1c3e5032447124dae47ae23ebf820fdcf8080588
Closes-Bug: #1380745
Cluster Error On Missing Volume Sizes Unoptimal

if the volume size is omitted on an instance, and volume_support
is true, then the error should indicate that the volume size
is missing, vs. stating that the volume sizes don't match.

Change-Id: I40c807313eaed4fb2f433da1c8a80089e01756fa
Closes-Bug: #1369001
Logging audit for guestagent/mongodb

Adjust logging to conform to logging standards.
Cleaned up a few messages that were unclear and changed several
LOG.info messages to LOG.debug.

Also fixed a pattern of exception handlers using LOG.error
merely to log the exception (instead of LOG.exception)

Change-Id: I3bd544b761b449d1181792ff498f9c171331df16
Partial-Bug: #1324206
Merge "fixing the flags for guest on resize volume"
Merge "Cluster Error On Missing Volume Sizes Unoptimal"
Merge "Logging audit for guestagent/mongodb"
Merge "cluster_config argument missing in prepare()"