JSCBC-711: Fixed issue with early shutdown of flush watcher.
JSCBC-711: Fixed issue with early shutdown of flush watcher.

Motivation
----------
Due to the placement of our setup code, it was possible for
the SDK to attempt to clean up our flush watcher before it
was set up, causing a segfault.

Changes
-------
Moved the flush watcher initialization to the constructor
of the Connection rather than being in the connect callback.

Change-Id: I840d70a8fea6d5029233c1f028b736355e8f542d
Reviewed-on: http://review.couchbase.org/124052
Reviewed-by: Michael Reiche <150818245b00123390f022db0bae4daa40ee9511@couchbase.com>
Tested-by: Brett Lawson <c8c4369773d7d7226e031f0c4af62e3f38a08510@gmail.com>

couchbase/couchnode,brett19/couchnode,couchbase/couchnode,couchbase/couchnode,couchbase/couchnode,brett19/couchnode,brett19/couchnode