Remove parameter "hasBeenSet" logic

It doesn't really make sense anymore given that settings might come
from the GUI or configuration and not only the command line.
diff --git a/tests/encperf.cxx b/tests/encperf.cxx
index 9b632e7..d93c771 100644
--- a/tests/encperf.cxx
+++ b/tests/encperf.cxx
@@ -427,12 +427,12 @@
     usage(argv[0]);
   }
 
-  if (!format.hasBeenSet()) {
+  if (strcmp(format, "") == 0) {
     fprintf(stderr, "Pixel format not specified!\n\n");
     usage(argv[0]);
   }
 
-  if (!width.hasBeenSet() || !height.hasBeenSet()) {
+  if (width == 0 || height == 0) {
     fprintf(stderr, "Frame buffer size not specified!\n\n");
     usage(argv[0]);
   }