Merge branch 'js/rebase-i-redo-exec'

"git rebase -i" learned to re-execute a command given with 'exec'
to run after it failed the last time.

* js/rebase-i-redo-exec:
rebase: introduce a shortcut for --reschedule-failed-exec
rebase: add a config option to default to --reschedule-failed-exec
rebase: introduce --reschedule-failed-exec

diff --cc Documentation/git-rebase.txt
Simple merge

diff --cc builtin/rebase--interactive.c
Simple merge

diff --cc builtin/rebase.c
Simple merge

diff --cc sequencer.c
Simple merge

diff --cc sequencer.h
Simple merge