JCBC-371: Removing redundant reference of bucket/vBucket.

This changeset removes the redundant this.bucket reference in
the BucketMonitor, reducing memory a bit. Also, the observe
notifiers are now called directly and the needed bucket
config is referenced from the parent ConfigurationProvider.

Change-Id: I0b044388d570b8e321c6285488d9f07b6c0f163d
Reviewed-on: http://review.couchbase.org/29714
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>