Add validation script for min env vars documentation

Change-Id: I46ffa01d0097916055857c3f968e716e0229795f
Partially-implements: blueprint add-min-env-vars-gate

tools/validate-min-env-vars.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+REAL_PATH=$(python -c "import os,sys;print os.path.realpath('$0')")
+cd "$(dirname "$REAL_PATH")/.."
+
+MIN_ENV_VARS_DOC=./docs/minimal-environment-vars.md
+
+mv ${MIN_ENV_VARS_DOC}{,.validate}
+
+# Generate a new file and check the content is the same
+./tools/min-env.sh
+/usr/bin/diff ${MIN_ENV_VARS_DOC}{,.validate}
+RET=$?
+
+mv ${MIN_ENV_VARS_DOC}{.validate,}
+
+exit $RET