[project][qemu] Fix NoneError on timeout

The call to recv in msg_channel_recv can fail if a timeout has occured
and self.msg_sock_conn has been set to None. Check if this has occured
and return a zero-length bytes object instead to fail gracefully.

Test: run boot test which times out
Bug: None
Change-Id: I56935475d8f6303ede4591d843fbfc8b3004a6ba
1 file changed
tree: 3985d7e786c22dc05eb9e89ca61adb9028e9f0e0
  1. project/
  2. .clang-format
  4. PREUPLOAD.cfg