Add definition to etrecord_path to the devtools tutorial (pytorch#5458)

Summary:
Pull Request resolved: pytorch#5458

This diff adds the definition for variable `etrecord_path`. `etrecord_path` was defined in previous steps in the tutorial, but when user gets to this step, they would usually start a new script, so we should define this variable again.

Reviewed By: Gasoonjia, dvorjackz

Differential Revision: D62921869

fbshipit-source-id: 1d274d5fc76f84f6f943295c142141051fd85cb4

Author: Olivia-liu

docs/source/tutorials_source/devtools-integration-tutorial.py

@@ -196,6 +196,7 @@ def forward(self, x):
 inspector_patch.start()
 inspector_patch_print.start()
 # sphinx_gallery_end_ignore
+etrecord_path = "etrecord.bin"
 etdump_path = "etdump.etdp"
 inspector = Inspector(etdump_path=etdump_path, etrecord=etrecord_path)
 # sphinx_gallery_start_ignore