Merge branch 'docs-update-usersapi' into 'master'

Adds a note about the case when reset_password is false

See merge request gitlab-org/gitlab-ce!21738

doc/api/users.md

@@ -263,7 +263,7 @@ GET /users/:id?with_custom_attributes=true
 ## User creation
-Creates a new user. Note only administrators can create new users. Either `password` or `reset_password` should be specified (`reset_password` takes priority).
+Creates a new user. Note only administrators can create new users. Either `password` or `reset_password` should be specified (`reset_password` takes priority). If `reset_password` is `false`, then `password` is required.
 ```
 POST /users