Make env vars script zsh-compatible

Author: szarnyasg

cypher/scripts/environment-variables-default.sh

@@ -1,6 +1,4 @@
-#!/bin/bash
-
-cd "$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+cd "$( cd "$( dirname "${BASH_SOURCE[0]:-${(%):-%x}}" )" >/dev/null 2>&1 && pwd )"
 cd ..
 
 export NEO4J_CONTAINER_ROOT=`pwd`/neo4j-scratch