Fallback to using taglist.log for listing commits in autorelease distributions when git.properties is not present

distchanges uses git.properties to find the last commit in the bundles, but autorelease builds have a local commit that is not checked into git - the last commit is used only for the build. The build doe include a taglist.log in the root of the distro that lists all the last commit hashes per bundle. That hash can be used by distchanges.