git-cherry-pick.txt: do not use 'ORIG_HEAD' in example

Commit 67ac1e1d57 (cherry-pick/revert: add support for
-X/--strategy-option, 2010-12-10) added an example to the documentation
of 'git cherry-pick'. This example mentions how to abort a failed
cherry-pick and retry with an additional merge strategy option.

The command used in the example to abort the cherry-pick is 'git reset
--merge ORIG_HEAD', but cherry-pick does not write 'ORIG_HEAD' before
starting its operation. So this command would checkout a commit
unrelated to what was at HEAD when the user invoked cherry-pick.

Use 'git cherry-pick --abort' instead.

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Acked-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-cherry-pick.txt

@@ -219,7 +219,7 @@ again, this time exercising more care about matching up context lines.
 ------------
 $ git cherry-pick topic^             <1>
 $ git diff                           <2>
-$ git reset --merge ORIG_HEAD        <3>
+$ git cherry-pick --abort            <3>
 $ git cherry-pick -Xpatience topic^  <4>
 ------------
 <1> apply the change that would be shown by `git show topic^`.