[UWS] Fix some constructors of UWSServer where the local variable for logger

(possibly NULL) was used instead of the class variable (which is NEVER NULL).

src/uws/service/UWSService.java

@@ -139,7 +139,7 @@ import uws.service.wait.BlockingPolicy;
  * </p>
  *
  * @author Gr&eacute;gory Mantelet (CDS;ARI)
- * @version 4.3 (11/2017)
+ * @version 4.4 (08/2018)
  */
 public class UWSService implements UWS {
 
@@ -337,7 +337,7 @@ public class UWSService implements UWS {
 			name = urlInterpreter.getUWSName();
 
 			// Log the successful initialization:
-			logger.logUWS(LogLevel.INFO, this, "INIT", "UWS successfully initialized!", null);
+			this.logger.logUWS(LogLevel.INFO, this, "INIT", "UWS successfully initialized!", null);
 
 		}catch(NullPointerException ex){
 			// Log the exception:
@@ -380,7 +380,7 @@ public class UWSService implements UWS {
 		this(jobFactory, fileManager, logger);
 		setUrlInterpreter(urlInterpreter);
 		if (this.urlInterpreter != null)
-			logger.logUWS(LogLevel.INFO, this, "INIT", "UWS successfully initialized.", null);
+			this.logger.logUWS(LogLevel.INFO, this, "INIT", "UWS successfully initialized.", null);
 	}
 
 	@Override