When the password file does not exist and we're making sure the user isn't in the password file, change error into a warning
When the password file does not exist and we're making sure the user isn't in the password file, change error into a warning

Warning catches typos in the filename.  Since the playbook is saying
"make sure this user doesn't have an entry" it makes more sense to warn
than to error.

Fixes #2619

thaim/ansible,thaim/ansible