change one more `touch` command to `install /dev/null` to prevent issues on fresh volumes (and for consistency with other usages)

Signed-off-by: Adam Warner <me@adamwarner.co.uk>

bash_functions.sh

@@ -47,7 +47,7 @@ prepare_configs() {
     installConfigs
    
     if [ ! -f "${setupVars}" ]; then
-        touch "${setupVars}"
+        install /dev/null "${setupVars}"
         echo "Creating empty ${setupVars} file."
     fi