CCBC-384: Don't abort on unrecognized WSA errors

Change-Id: Ic5ca12dc35d337ab9fde176bc13ccb69034ca143
Reviewed-on: http://review.couchbase.org/36140
Reviewed-by: Yury Alioshinov <haster2010@gmail.com>
Tested-by: Yury Alioshinov <haster2010@gmail.com>
Reviewed-by: Brett Lawson <brett19@gmail.com>