Fixed '--version' for trove processes/utilities

The trove processes (trove-manage, trove-conductor, trove-api, etc.)
returned an empty string when invoked with --version. They now return
the correct version string.

Change-Id: Ic14597e30928c753eae3090b401fbd66e042b93b
Closes-Bug: #1338767
Add instance IP to /instances

This new response will be used by Horizon instead of the 1+N calls
Horizon makes today in order to render IPs in the instances list

Change-Id: Ice8f07cdaf873034dc7dc8840fcc403b4756ac12
Closes-Bug: #1339400
Stop cassandra during configuration and volume migration

The cassandra service is left running after installation.
The next operation(s) are to rewrite the configuration, and
migrate the data onto a volume (if provided). It is not a
good thing for the database to be running during the latter,
and a restart is required after the former.

Failing to stop the database during the data migration can
result in an rsync error 24 because files that were present
when rsync made its list may be missing by the time rsync
gets around to trying to sync that file. This can lead rsync
to not make a 'true' copy of the source on the destination.

The only way around this is to stop the database, something
that is already done by both MongoDB and MySQL in their
guest agents.

Change-Id: I74ecc5c12d43eccc6295488e344bc0e75fe8116d
Closes-bug: #1338660
Merge "Fixed '--version' for trove processes/utilities"
Merge "Add instance IP to /instances"
Merge "Stop cassandra during configuration and volume migration"