In 2.29, "--committer-date-is-author-date" option of "rebase" and
"am" subcommands lost the e-mail address by mistake, which has been
corrected.
* jk/committer-date-is-author-date-fix:
rebase: fix broken email with --committer-date-is-author-date
am: fix broken email with --committer-date-is-author-date
t3436: check --committer-date-is-author-date result more carefully