Merge branch 'js/rebase-merges-exec-fix'

The "--exec" option to "git rebase --rebase-merges" placed the exec
commands at wrong places, which has been corrected.

* js/rebase-merges-exec-fix:
rebase --exec: make it work with --rebase-merges
t3430: demonstrate what -r, --autosquash & --exec should do

diff --cc sequencer.c
Simple merge