Fixed bug in http code.

Removed callback invocation which is leaking non-couchnode
errors.  The error is already naturally handled in the block
following it.

Change-Id: I3d7b3c4c7294eab9c0dfbb22cc65f77e235e5f74
Reviewed-on: http://review.couchbase.org/30119
Reviewed-by: Matt Ingenthron <matt@couchbase.com>
Tested-by: Brett Lawson <brett19@gmail.com>