Merge branch 'mg/log-decorate-HEAD' into maint

The "log --decorate" enhancement in Git 2.4 that shows the commit at the tip of the current branch e.g. "HEAD -> master", did not work with --decorate=full. * mg/log-decorate-HEAD: log: do not shorten decoration names too early log: decorate HEAD with branch name under --decorate=full, too