Remove validate-maintainer.sh script

This script is only required in the kolla repository.

Change-Id: I80109d28dc196f489f4a6a73f970a279a9070ce1

tools/validate-maintainer.sh

@@ -1,13 +0,0 @@
-#!/bin/bash
-
-MAINTAINER='MAINTAINER {{ maintainer }}'
-RES=0
-
-for dockerfile in "$@"; do
-    if ! grep -q "$MAINTAINER" "$dockerfile"; then
-        echo "ERROR: $dockerfile has incorrect MAINTAINER" >&2
-        RES=1
-    fi
-done
-
-exit $RES