Do not use readlink -f

- Does not work on macs

Co-authored-by: Tyler Phelan <tphelan@pivotal.io>

Author: Ben16

scripts/unit.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-export ROOT=`dirname $(readlink -f ${BASH_SOURCE%/*})`
+export ROOT="$( dirname "$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )" )"
 $ROOT/scripts/install_tools.sh
 
 cd $ROOT/src/binary/