Importing rustc-1.49.0

Bug: 176888219
Change-Id: Ib0805d37e7b485cd420bbff8a8b000cf87e7ede0
diff --git a/src/ci/docker/scripts/rustbuild-setup.sh b/src/ci/docker/scripts/rustbuild-setup.sh
index 94d7e60..baf2a68 100644
--- a/src/ci/docker/scripts/rustbuild-setup.sh
+++ b/src/ci/docker/scripts/rustbuild-setup.sh
@@ -1,3 +1,4 @@
+#!/bin/sh
 set -ex
 
 groupadd -r rustbuild && useradd -m -r -g rustbuild rustbuild