JSCBC-159: Disconnect callback and destroy instance on bootstrap error.

Libcouchbase can potentially return timeout errors during bootstrapping,
that are later resolved and connection succeeds.  This causes odd logic
problems in higher level languages.

Change-Id: Ief014085877de1e9f8e2f0f4a77da20e46d77fe1
Reviewed-on: http://review.couchbase.org/43014
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>
Tested-by: Brett Lawson <brett19@gmail.com>