replace grep+sed by awk

cdist/conf/explorer/os

@@ -143,7 +143,7 @@ esac
 if [ -f /etc/os-release ]; then
    # already lowercase, according to:
    # https://www.freedesktop.org/software/systemd/man/os-release.html
-   grep '^ID=' /etc/os-release | sed -e 's|^ID=||'
+   awk -F= '/^ID=/ {print $2;}' /etc/os-release
    exit 0
 fi