load_weights() now properly closes file (keras-team#13048)

In certain use cases, load_weights() would cause OSError if called repeatedly on many different files. The proposed addition will now make sure the HDF5 files are closed before exiting.

keras/engine/network.py

@@ -1215,6 +1215,10 @@ def load_weights(self, filepath, by_name=False,
             else:
                 saving.load_weights_from_hdf5_group(
                     f, self.layers, reshape=reshape)
+            if hasattr(f, 'close'):
+                f.close()
+            elif hasattr(f.file, 'close'):
+                f.file.close()
 
     def _updated_config(self):
         """Util hared between different serialization methods.