MDL-40613 auth: moved lang string to common auth file

Also fixed call to get_string() and defined var 'errorlogtag'
in base class.

AMOS BEGIN
 MOV [auth_dbusernotexist,auth_db],[auth_usernotexist,auth]
AMOS END

auth/db/auth.php

@@ -42,6 +42,7 @@ function __construct() {
 
         $this->authtype = 'db';
         $this->config = get_config('auth_db');
+        $this->errorlogtag = '[AUTH DB] ';
         if (empty($this->config->extencoding)) {
             $this->config->extencoding = 'utf-8';
         }

auth/db/lang/en/auth_db.php

@@ -66,7 +66,6 @@
 $string['auth_dbupdatinguser'] = 'Updating user {$a->name} id {$a->id}';
 $string['auth_dbuser'] = 'Username with read access to the database';
 $string['auth_dbuser_key'] = 'DB user';
-$string['auth_dbusernotexist'] = 'Cannot update non-existent user: {$a}';
 $string['auth_dbuserstoadd'] = 'User entries to add: {$a}';
 $string['auth_dbuserstoremove'] = 'User entries to remove: {$a}';
 $string['pluginname'] = 'External database';

lang/en/auth.php

@@ -64,6 +64,7 @@
 $string['auth_user_create'] = 'Enable user creation';
 $string['auth_user_creation'] = 'New (anonymous) users can create user accounts on the external authentication source and confirmed via email. If you enable this , remember to also configure module-specific options for user creation.';
 $string['auth_usernameexists'] = 'Selected username already exists. Please choose a new one.';
+$string['auth_usernotexist'] = 'Cannot update non-existent user: {$a}';
 $string['auto_add_remote_users'] = 'Auto add remote users';
 $string['cannotmapfield'] = 'Field "{$a->fieldname}" can not be mapped because its short name "{$a->shortname}" is too long. To enable mapping reduce the profile field short name down to {$a->charlimit} characters. <a href="{$a->link}">Edit user profile fields</a>';
 $string['createpassword'] = 'Generate password and notify user';

lib/authlib.php

@@ -110,6 +110,13 @@ class auth_plugin_base {
      */
     var $customfields = null;
 
+    /**
+     * The tag we want to prepend to any error log messages.
+     *
+     * @var string
+     */
+    protected $errorlogtag = '';
+
     /**
      * This is the primary method that is used by the authenticate_user_login()
      * function in moodlelib.php.
@@ -641,8 +648,8 @@ protected function update_user_record($username, $updatekeys = false, $triggerev
         // Get the current user record.
         $user = $DB->get_record('user', array('username' => $username, 'mnethostid' => $CFG->mnet_localhost_id));
         if (empty($user)) { // Trouble.
-            error_log($this->errorlogtag.get_string('auth_dbusernotexist', 'auth_db', '', $username));
-            print_error('auth_dbusernotexist', 'auth_db', '', $username);
+            error_log($this->errorlogtag . get_string('auth_usernotexist', 'auth', $username));
+            print_error('auth_usernotexist', 'auth', '', $username);
             die;
         }