library/ipajoin.py: Enhanced tests for password and keytab

mutually_exclusive and required_one_of are only able to check if the parameters
are defined, but not if they are set to "".

library/ipajoin.py

@@ -202,8 +202,6 @@ def main():
             kinit_attempts=dict(required=False, type='int', default=5),
             debug=dict(required=False, type='bool'),
         ),
-        mutually_exclusive = [['password','keytab']],
-        required_one_of = [['password', 'keytab']],
         supports_check_mode = True,
     )
 
@@ -222,6 +220,10 @@ def main():
     kinit_attempts = module.params.get('kinit_attempts')
     debug = module.params.get('debug')
 
+    if password is not None and password != "" and \
+       keytab is not None and keytab != "":
+        module.fail_json(msg="Password and keytab cannot be used together")
+
     client_domain = hostname[hostname.find(".")+1:]
     nolog = tuple()
     env = {'PATH': SECURE_PATH}