Fixed backward compatibility issue

Author: Nikhil Bhoski

src/main/java/com/mathworks/ci/RunMatlabTestsBuilder.java

@@ -207,19 +207,19 @@ private Artifact getArtifactObject(boolean isChecked, Artifact returnVal)  {
     // Verbosity level
 
     public String getLoggingLevel() {
-        return loggingLevel;
+        return loggingLevel == null ? "default" : this.loggingLevel;
     }
 
     public String getOutputDetail() {
-        return outputDetail;
+        return outputDetail == null ? "default" : this.outputDetail;
     }
 
     public boolean getStrict() {
-        return strict;
+        return this.strict;
     }
 
     public boolean getUseParallel() {
-        return useParallel;
+        return this.useParallel;
     }