specify explicit "--pretty=medium" with `git log/show/whatchanged`

The following patch will introduce a new configuration variable,
"format.pretty", from then on the pretty format without specifying
"--pretty" might not be the default "--pretty=medium", it depends on
the user's config. So all kinds of Shell/Perl/Emacs scripts that needs
the default medium pretty format must specify it explicitly.

Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/emacs/git.el

@@ -1299,7 +1299,7 @@ Return the list of files that haven't been handled."
   (let (author-name author-email subject date msg)
     (with-temp-buffer
       (let ((coding-system (git-get-logoutput-coding-system)))
-        (git-call-process-env t nil "log" "-1" commit)
+        (git-call-process-env t nil "log" "-1" "--pretty=medium" commit)
         (goto-char (point-min))
         (when (re-search-forward "^Author: *\\(.*\\) <\\(.*\\)>$" nil t)
           (setq author-name (match-string 1))

contrib/hooks/post-receive-email

@@ -567,7 +567,7 @@ generate_general_email()
 	echo ""
 	if [ "$newrev_type" = "commit" ]; then
 		echo $LOGBEGIN
-		git show --no-color --root -s $newrev
+		git show --no-color --root -s --pretty=medium $newrev
 		echo $LOGEND
 	else
 		# What can we do here?  The tag marks an object that is not

git-cvsserver.perl

@@ -2556,7 +2556,7 @@ sub update
                     if ($base) {
                         my @merged;
                         # print "want to log between  $base $parent \n";
-                        open(GITLOG, '-|', 'git-log', "$base..$parent")
+                        open(GITLOG, '-|', 'git-log', '--pretty=medium', "$base..$parent")
 			  or die "Cannot call git-log: $!";
                         my $mergedhash;
                         while (<GITLOG>) {

git-merge.sh

@@ -71,7 +71,7 @@ finish_up_to_date () {
 squash_message () {
 	echo Squashed commit of the following:
 	echo
-	git log --no-merges ^"$head" $remoteheads
+	git log --no-merges --pretty=medium ^"$head" $remoteheads
 }
 
 finish () {