Also updates error message

git-svn-id: http://dev.piwik.org/svn/trunk@4095 59fd770c-687e-43c8-a1e3-f5a4ff64c105

lang/en.php

@@ -1138,7 +1138,7 @@ $translations = array(
 	'UsersManager_YourUsernameCannotBeChanged' => 'Your username cannot be changed.',
 	'UsersManager_ExceptionLoginExists' => 'Login \'%s\' already exists.',
 	'UsersManager_ExceptionEmailExists' => 'User with email \'%s\' already exists.',
-	'UsersManager_ExceptionInvalidLoginFormat' => 'The login must be between %1$s and %2$s characters long and contain only letters, numbers, or the characters \'_\' or \'-\' or \'.\' or \'@\'',
+	'UsersManager_ExceptionInvalidLoginFormat' => 'The login must be between %1$s and %2$s characters long and contain only letters, numbers, or the characters \'_\' or \'-\' or \'.\' or \'@\' or \'+\'',
 	'UsersManager_ExceptionInvalidPassword' => 'The password length must be between 6 and 26 characters.',
 	'UsersManager_ExceptionInvalidEmail' => 'The email doesn\'t have a valid format.',
 	'UsersManager_ExceptionDeleteDoesNotExist' => 'User \'%s\' doesn\'t exist therefore it can\'t be deleted.',