MB-8991: Remove typo in assignment

The statement "password == NULL" have no effect and
emits a warning that may cause a build break depending on the
compilers setting. In this case the password variable isn't used
either due to the fact that the password length == 0

Change-Id: Ic8fb0023cd82badd418b235d5055de3d508c4fcc
Reviewed-on: http://review.couchbase.org/28626
Reviewed-by: Michael Wiederhold <mike@couchbase.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>