Small fixups

- get condition for hostname right.
- add missing migrations module to service
- replace provider reference with CuratorFramework
Make leader only pollers only run when the instance is the leader.
LeaderOnlyPollers should only run when the Mesos Scheduler is running, too.
SingularityAbort now shuts down through the Dropwizard Lifecycle.

This gives the rest of the code a shot at doing a clean shutdown.
abort cleanup and minor style fixes
remove unnecessary mesosScheduler variable
cleanup merge
fix missing dependency
styling
Merge remote-tracking branch 'upstream/hs_guice_changes' into guice-changes
Use a provider to sling the server around.
jesos changes