Remove the annoying WVStreamControl version prints from command line test apps

Change-Id: I946c4e62a68b2bf9a10ad957feb9424aa606755e

proprietary/wvm/WVMExtractorImpl.cpp

@@ -83,6 +83,7 @@ bool IsWidevineMedia(const sp<DataSource>& dataSource) {
         return false;
     }
 
+    setenv("WV_SILENT", "true", 1);
     bool result = WV_IsWidevineMedia(buffer, sizeof(buffer));
     return result;
 }