Fixing help text based on feedback

mattermost.go

@@ -328,9 +328,9 @@ Usage:
         Example:
             platform -create_user -team_name="name" -email="user@example.com" -password="mypassword"
 
-    -assign_role                      Assigns role to a user.  It requres the -team_name,
-                                      -email and -role flag.  If you're assigning the
-                                      "system_admin" role it must be for a user on the
+    -assign_role                      Assigns role to a user.  It requres the -role,
+                                      -email and -team_name flag.  If you're assigning the
+                                      role="system_admin" role it must be for a user on the
                                       team_name="admin"
         Example:
             platform -assign_role -team_name="name" -email="user@example.com" -role="admin"