JSCBC-799: Updated error handling for deferred operations.
JSCBC-799: Updated error handling for deferred operations.

Motivation
----------
When operations were deferred waiting for a connect to complete,
those operations throwing exceptions would sometimes bubble
incorrectly through the deferment process.

Changes
-------
Added explicit handling of the case where an exception is thrown
during the dispatch of an operation and forward it through to the
callback instead.

Change-Id: I240b87224f5578be54049c0ca380c461406aa8bb
Reviewed-on: http://review.couchbase.org/c/couchnode/+/138788
Reviewed-by: David Kelly <d83cd2a93a916ce0b0d4c1349b44be044799feca@gmail.com>
Tested-by: Brett Lawson <c8c4369773d7d7226e031f0c4af62e3f38a08510@gmail.com>

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