MDL-27171 messages: implement new syntax in messages.php and update processing

The new messaging default settings can be set in messages.php and deployed
during installation. This also ensures the removing of settings on plugin
uninstallation and contains the update script to populate current default
settings on the existing system when the new feature is introduced.

For security reason we have to avoid using library functions in upgrade
function, so we set defaults the blind way. At this point we do not expect
plugins to have individual messaging defaults presets anyway. The site
defaults are the same as were set for each user using
message_set_default_message_preferences function.

Signed-off-by: Ruslan Kabalin <[email protected]>

user/editadvanced.php

@@ -200,10 +200,6 @@ if ($usernew = $userform->get_data()) {
 
     // trigger events
     if ($usercreated) {
-        //set default message preferences
-        if (!message_set_default_message_preferences( $usernew )){
-            print_error('cannotsavemessageprefs', 'message');
-        }
         events_trigger('user_created', $usernew);
     } else {
         events_trigger('user_updated', $usernew);