Cleanup `.watchman` file (#114716)

This seems to be an artifact from an fb tool that snuck into a commit (#113117)? CC @malfet
Pull Request resolved: https://github.com/pytorch/pytorch/pull/114716
Approved by: https://github.com/mikaylagawarecki, https://github.com/yanboliang, https://github.com/malfet
diff --git a/.watchman b/.watchman
deleted file mode 100644
index 0967ef4..0000000
--- a/.watchman
+++ /dev/null
@@ -1 +0,0 @@
-{}