Fix check-headers script
#!/bin/sh
-files=$(find . -name \*.go -type f -print0 | xargs -0 egrep -L '(Licensed under the Apache License)|(Code generated from|by)')
+files=$(find . -name \*.go -type f -print0 | xargs -0 grep -L -E '(Licensed under the Apache License)|(Code generated (from|by))')
if [ -n "$files" ]; then
echo "Missing license header in:"
echo "$files"
