[FIX] overwrite user id correctly for notificationnew
[FIX] overwrite user id correctly for notificationnew

notificationnew accepts an option --user to overwrite the user given in
the YAML or taken from %ENV. This overwrite did not work correctly. To
overwrite we need to unset the user_id field but did unset the
user_login field right after it was set. Fixed.

tapper/Tapper-CLI