bash completion: Update 'git am' options

This adds --committer-date-is-author-date, --ignore-date, and --no-utf8
options.  The --binary option is removed, as it was made a no-op by
cb3a160d.  The option list is also sorted alphabetically.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.bash

@@ -646,7 +646,8 @@ _git_am ()
 		;;
 	--*)
 		__gitcomp "
-			--signoff --utf8 --binary --3way --interactive
+			--3way --committer-date-is-author-date --ignore-date
+			--interactive --keep --no-utf8 --signoff --utf8
 			--whitespace=
 			"
 		return