Return error if connect fails
Return error if connect fails

Motivation
----------
In the future if connect fails then we want to keep retrying behind
the scenes. For now, we just want to return an error if we cannot
connect.

Changes
-------
Altered connectWithBucket to return an error if no nodes
could be contacted or no config could be fetched.

Change-Id: Ia43b54b1464955c1252b7aa691d04f30fe3a0cb0
Reviewed-on: http://review.couchbase.org/114595
Reviewed-by: Brett Lawson <c8c4369773d7d7226e031f0c4af62e3f38a08510@gmail.com>
Tested-by: Charles Dixon <e13bf4498b4994e133fd3586350658dc4a59329a@gmail.com>

brett19/gocbcore