Recommend enabling integrity-checking in git

* admin/notes/git-workflow:  Recommend setting transfer.fsckObjects.

This is related to the autogen.sh changes made by Paul Eggert in
commit d766ca8f (2016-02-01) and commit cedd7cad (2016-02-01), and to
my edits today to http://www.emacswiki.org/emacs/GitForEmacsDevs and
to emacswiki.org/emacs/GitQuickStartForEmacsDevs.  See also the thread
"Recommend these .gitconfig settings for git integrity." at
https://lists.gnu.org/archive/html/emacs-devel/2016-01/threads.html#01802.

admin/notes/git-workflow

@@ -9,6 +9,11 @@ If you haven't configured git before you should first do:
 
 git config --global user.name "Frank Chu"
 git config --global user.email "fchu@example.com"
+git config --global transfer.fsckObjects true
+
+(See the thread "Recommend these .gitconfig settings for git integrity."
+[https://lists.gnu.org/archive/html/emacs-devel/2016-01/threads.html#01802]
+for more details about why that last line is there.)
 
 Initial setup
 =============