Replace hardcoded error code with ENODATA (#3277)

The video reader suppressed code 61 (ENODATA on Linux) that occured at
the end of a stream and logged an INFO message. On macOS ENODATA has a
different code (96), which resulted in an error message being logged.

This small patch replaces the hard-coded value with the ENODATA constant
to suppress the macOS warning.
Co-authored-by: Vasilis Vryniotis <datumbox@users.noreply.github.com>

torchvision/csrc/io/video/Video.cpp

@@ -311,8 +311,8 @@ std::tuple<torch::Tensor, double> Video::Next() {
     // currently not supporting other formats (will do soon)
 
     out.payload.reset();
-  } else if (res == 61) {
-    LOG(INFO) << "Decoder ran out of frames (error 61)\n";
+  } else if (res == ENODATA) {
+    LOG(INFO) << "Decoder ran out of frames (ENODATA)\n";
   } else {
     LOG(ERROR) << "Decoder failed with ERROR_CODE " << res;
   }