Cleanup shm at startup in message_bridge_test

When we start forwarding messages from before connection, we need shm to
be clean.  Take this oppertunity to dedup some things.

Change-Id: Ic4caff28ba63e48ce5e74a28868deb5c808a984d
diff --git a/WORKSPACE b/WORKSPACE
index bcdbf4f..6c9949d 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -169,6 +169,7 @@
 http_archive(
     name = "arm_frc_linux_gnueabi_repo",
     build_file = "@//tools/cpp/arm-frc-linux-gnueabi:arm-frc-linux-gnueabi.BUILD",
+    patches = ["//debian:fts.patch"],
     sha256 = "043a5b047c2af9cf80d146d8327b588264c98a01e0f3f41e3564dd2bbbc95c0e",
     strip_prefix = "frc2020/roborio/",
     url = "https://www.frc971.org/Build-Dependencies/FRC-2020-Linux-Toolchain-7.3.0.tar.gz",