Merge branch 'jk/read-commit-buffer-data-after-free'

Clarify the ownership rule for commit->buffer field, which some callers incorrectly accessed without making sure it is populated. * jk/read-commit-buffer-data-after-free: logmsg_reencode: lazily load missing commit buffers logmsg_reencode: never return NULL commit: drop useless xstrdup of commit message