Cleanup gerrit ACLs

For consistency accross all ACLs, remove usage
of "refs/*" section and replace with:
* Move create ACLs for branches to "ref/heads/*".
* Move pushSignedTag to "refs/tags/*"

Change-Id: I8648a7b7b245921ddf7146fd9da31ea7b5e31d9d
Merge "Cleanup gerrit ACLs"