pyrun: fix quoting

BUG=None
TEST=None

Change-Id: Ieed7e7df9bed83dc6c54d687ae3f3ae657e22693
Reviewed-on: https://chromium-review.googlesource.com/1168457
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Luis Lozano <llozano@chromium.org>
diff --git a/pyrun b/pyrun
index d9f5d75..9aac2f2 100755
--- a/pyrun
+++ b/pyrun
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-DIRECTORY=$(cd `dirname $0` && pwd)
-PYTHONPATH=$DIRECTORY:$PYTHONPATH
+DIRECTORY=$(cd "$(dirname "$0")" && pwd)
+export PYTHONPATH="${DIRECTORY}:${PYTHONPATH}"
 
-$*
+"$@"