Merge branch 'jk/committer-date-is-author-date-fix' into maint

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