Adjust method name

Signed-off-by: Joas Schilling <coding@schilljs.com>

lib/Migration/FillRoomTokens.php

@@ -92,7 +92,7 @@ class FillRoomTokens implements IRepairStep {
 		$query = $this->connection->getQueryBuilder();
 		$query->select('*')
 			->from('spreedme_rooms')
-			->where($query->expr()->isEmptyString('token'));
+			->where($query->expr()->emptyString('token'));
 		$result = $query->execute();
 
 		$output->startProgress();

lib/Migration/Version2001002Date20170707115443.php

@@ -123,7 +123,7 @@ class Version2001002Date20170707115443 extends SimpleMigrationStep {
 
 		$update->update('spreedme_room_participants')
 			->set('participantType', $update->createNamedParameter(Participant::MODERATOR))
-			->where($update->expr()->isNotEmptyString('userId'))
+			->where($update->expr()->nonEmptyString('userId'))
 			->andWhere($update->expr()->notIn('roomId', $update->createNamedParameter($one2oneRooms, IQueryBuilder::PARAM_INT_ARRAY)));
 
 		return $update->execute();

lib/Room.php

@@ -209,7 +209,7 @@ class Room {
 			$query = $this->db->getQueryBuilder();
 			$query->delete('spreedme_room_participants')
 				->where($query->expr()->eq('roomId', $query->createNamedParameter($this->getId(), IQueryBuilder::PARAM_INT)))
-				->andWhere($query->expr()->isEmptyString('userId'));
+				->andWhere($query->expr()->emptyString('userId'));
 			$query->execute();
 		}
 
@@ -341,7 +341,7 @@ class Room {
 		$query = $this->db->getQueryBuilder();
 		$query->delete('spreedme_room_participants')
 			->where($query->expr()->eq('roomId', $query->createNamedParameter($this->getId(), IQueryBuilder::PARAM_INT)))
-			->andWhere($query->expr()->isEmptyString('userId'))
+			->andWhere($query->expr()->emptyString('userId'))
 			->andWhere($query->expr()->lte('lastPing', $query->createNamedParameter(time() - 30, IQueryBuilder::PARAM_INT)));
 		$query->execute();
 	}