Remove unused StringUtils import

Replaced StringUtils from Apache Commons Lang with local one.

Author: DaanHoogland

server/src/main/java/com/cloud/user/DomainManagerImpl.java

@@ -90,6 +90,7 @@
 import com.cloud.storage.dao.VolumeDao;
 import com.cloud.user.dao.AccountDao;
 import com.cloud.utils.Pair;
+import com.cloud.utils.StringUtils;
 import com.cloud.utils.component.ManagerBase;
 import com.cloud.utils.db.DB;
 import com.cloud.utils.db.Filter;
@@ -106,8 +107,6 @@
 import com.cloud.vm.ReservationContextImpl;
 import com.cloud.vm.dao.VMInstanceDao;
 
-import org.apache.commons.lang3.StringUtils;
-
 @Component
 public class DomainManagerImpl extends ManagerBase implements DomainManager, DomainService {