Update .gitmodules

Author: abitofhelp

.gitmodules

@@ -7,6 +7,3 @@
 [submodule "go-astream-file-between-goroutines-with-refcntpool"]
 	path = go-astream-file-between-goroutines-with-refcntpool
 	url = https://gist.github.com/b5f3eebf7e316b96b2cdc4188db2d742.git
-[submodule "go-stream-file-between-goroutines-with-linux-pipe"]
-	path = go-stream-file-between-goroutines-with-linux-pipe
-	url = https://gist.github.com/3e6ed3487519217b09281815aced2af9.git