fix "Task pending" error message when closing odrivetool

CHANGELOG.md

@@ -5,6 +5,7 @@ Please add a note of your changes below this heading if you make a Pull Request.
 ## [0.5.3] - unreleased
 ### Fixed
 * ASCII protocol commands with multiline responses (`i`, `h`) now return the expected response (in v0.5.2 the response was corrupted)
+* odrivetool no longer shows the message `<Task pending coro=... running at ...>` when closing
 
 # Releases
 ## [0.5.2] - 2021-05-21

tools/odrive/pyfibre/fibre/shell.py

@@ -148,3 +148,4 @@ def launch_shell(args, mount,
         interact()
 
         shutdown_token[0] = True
+        discovery.stop()