Merge branch 'ws/rebase-p'

Code clean-up.

* ws/rebase-p:
  rebase: remove merges_option and a blank line
  rebase: remove unused code paths from git_rebase__interactive__preserve_merges
  rebase: remove unused code paths from git_rebase__interactive
  rebase: add and use git_rebase__interactive__preserve_merges
  rebase: extract functions out of git_rebase__interactive
  rebase: reindent function git_rebase__interactive
  rebase: update invocation of rebase dot-sourced scripts
  rebase-interactive: simplify pick_on_preserving_merges

Author: gitster

git-rebase--am.sh

@@ -4,15 +4,6 @@
 # Copyright (c) 2010 Junio C Hamano.
 #
 
-# The whole contents of this file is run by dot-sourcing it from
-# inside a shell function.  It used to be that "return"s we see
-# below were not inside any function, and expected to return
-# to the function that dot-sourced us.
-#
-# However, older (9.x) versions of FreeBSD /bin/sh misbehave on such a
-# construct and continue to run the statements that follow such a "return".
-# As a work-around, we introduce an extra layer of a function
-# here, and immediately call it after defining it.
 git_rebase__am () {
 
 case "$action" in
@@ -105,5 +96,3 @@ fi
 move_to_original_branch
 
 }
-# ... and then we call the whole thing.
-git_rebase__am