Merge branch 'jk/rebase-quiet-noop' into maint

"git rebase --quiet" was not quite quiet when there is nothing to
do.

* jk/rebase-quiet-noop:
rebase: silence "git checkout" for noop rebase

diff --combined git-rebase.sh
index 55da9db818665f39ed205d3c77352987e3ca9963,ba74d11941d3b714797d6a7bff6f85747b602e6a..90854e38cb9ceb6985a5d7bd9faae722ed92361f
--- 1/git-rebase.sh
--- 2/git-rebase.sh
+++ b/git-rebase.sh
@@@ -59,7 -59,6 +59,7 @@@ If you prefer to skip this patch, run "
  To check out the original branch and stop rebasing, run "git rebase --abort".')
  "
  unset onto
 +unset restrict_revision
  cmd=
  strategy=
  strategy_opts=
@@@ -467,8 -466,8 +467,8 @@@ the
  else
        if test -z "$onto"
        then
 -              empty_tree=`git hash-object -t tree /dev/null`
 -              onto=`git commit-tree $empty_tree </dev/null`
 +              empty_tree=$(git hash-object -t tree /dev/null)
 +              onto=$(git commit-tree $empty_tree </dev/null)
                squash_onto="$onto"
        fi
        unset upstream_name
@@@ -526,10 -525,10 +526,10 @@@ case "$#" i
        ;;
  0)
        # Do not need to switch branches, we are already on it.
 -      if branch_name=`git symbolic-ref -q HEAD`
 +      if branch_name=$(git symbolic-ref -q HEAD)
        then
                head_name=$branch_name
 -              branch_name=`expr "z$branch_name" : 'zrefs/heads/\(.*\)'`
 +              branch_name=$(expr "z$branch_name" : 'zrefs/heads/\(.*\)')
        else
                head_name="detached HEAD"
                branch_name=HEAD ;# detached
@@@ -547,7 -546,7 +547,7 @@@ the
                        "${switch_to:-HEAD}")
        if test -n "$new_upstream"
        then
 -              upstream=$new_upstream
 +              restrict_revision=$new_upstream
        fi
  fi
  
@@@ -573,7 -572,7 +573,7 @@@ require_clean_work_tree "rebase" "$(get
  # and if this is not an interactive rebase.
  mb=$(git merge-base "$onto" "$orig_head")
  if test "$type" != interactive && test "$upstream" = "$onto" &&
 -      test "$mb" = "$onto" &&
 +      test "$mb" = "$onto" && test -z "$restrict_revision" &&
        # linear history?
        ! (git rev-list --parents "$onto".."$orig_head" | sane_grep " .* ") > /dev/null
  then
@@@ -582,7 -581,7 +582,7 @@@
                # Lazily switch to the target branch if needed...
                test -z "$switch_to" ||
                GIT_REFLOG_ACTION="$GIT_REFLOG_ACTION: checkout $switch_to" \
-                       git checkout "$switch_to" --
+                       git checkout -q "$switch_to" --
                say "$(eval_gettext "Current branch \$branch_name is up to date.")"
                finish_rebase
                exit 0
@@@ -627,7 -626,7 +627,7 @@@ if test -n "$rebase_root
  then
        revisions="$onto..$orig_head"
  else
 -      revisions="$upstream..$orig_head"
 +      revisions="${restrict_revision-$upstream}..$orig_head"
  fi
  
  run_specific_rebase