do not check rows affected when updating credential count
do not check rows affected when updating credential count

This is because if a row is updated to the value it already has then it
will report that no rows are affected. This is definitely possible if no
credentials have been added or removed from a repository.

[#133222515]

Signed-off-by: Christopher Brown <eb0819782e2e967e3d4f4d71eab0c647ed2659cf@pivotal.io>

pivotal-cf/cred-alert,pivotal-cf/cred-alert