Merge branch 'w15_MDL-32263_m23_enroladmin' of git://github.com/skodak/moodle

diff --combined lib/enrollib.php
index e02a4f7,ada83dd..c90139d
--- 1/lib/enrollib.php
--- 2/lib/enrollib.php
+++ b/lib/enrollib.php
@@@ -204,11 -204,8 +204,8 @@@ function enrol_check_plugins($user) 
          return;
      }
  
-     if (is_siteadmin()) {
-         // no sync for admin user, please use admin accounts only for admin tasks like the unix root user!
-         // if plugin fails on sync admins need to be able to log in and fix the settings
-         return;
-     }
+     // originally there was a broken admin test, but accidentally it was non-functional in 2.2,
+     // which proved it was actually not necessary.
  
      static $inprogress = array();  // To prevent this function being called more than once in an invocation
  
@@@ -264,8 -261,8 +261,8 @@@ function enrol_sharing_course($user1, $
  function enrol_get_shared_courses($user1, $user2, $preloadcontexts = false, $checkexistsonly = false) {
      global $DB, $CFG;
  
 -    $user1 = !empty($user1->id) ? $user1->id : $user1;
 -    $user2 = !empty($user2->id) ? $user2->id : $user2;
 +    $user1 = isset($user1->id) ? $user1->id : $user1;
 +    $user2 = isset($user2->id) ? $user2->id : $user2;
  
      if (empty($user1) or empty($user2)) {
          return false;