patchbomb: fix From_ in the message's envelope
Localized date in the From_ prevents MUAs like mutt from parsing mbox files
generated by patchbomb. Using a 24 characters date in asctime format instead.
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
created new head
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)