cros_run_bvt: source common.sh directly

This is the last script that loads the installed common.sh script.
Since this must be inside the chroot, have it source the file from
its source location directly instead.

BUG=None
TEST=`./cros_run_bvt --help` still works

Change-Id: I1659f74208e42c717ed55ad165bd0406badd5285
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/1843233
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/cros_run_bvt b/cros_run_bvt
index 73107e1..55e81fb 100755
--- a/cros_run_bvt
+++ b/cros_run_bvt
@@ -6,11 +6,11 @@
 # This script requires that you run build_packages first.
 
 # Special because this can only run inside the chroot.
-if [ ! -r /usr/lib/crosutils/common.sh ]; then
+if [ ! -r /mnt/host/source/src/scripts/common.sh ]; then
   echo "Must run within chroot" >&2
   exit 1
 fi
-. /usr/lib/crosutils/common.sh
+. /mnt/host/source/src/scripts/common.sh
 
 
 # Flags