t9800: correct misuse of 'show -s --raw' in a test

There is $(git show -s --raw --pretty=format:%at HEAD) in this test
that is meant to grab the author time of the commit.  We used to
have a bug in the command line option parser of the diff family of
commands, where "show -s --raw" was identical to "show -s".

With the "-s" bug fixed, "show -s --raw" would mean the same thing
as "show --raw", i.e. show the output from the diff machinery in the
"raw" format.  And this test will start failing, so fix it before
that happens.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9800-git-p4-basic.sh

@@ -330,7 +330,7 @@ test_expect_success 'initial import time from top change time' '
 	test_when_finished cleanup_git &&
 	(
 		cd "$git" &&
-		gittime=$(git show -s --raw --pretty=format:%at HEAD) &&
+		gittime=$(git show -s --pretty=format:%at HEAD) &&
 		echo $p4time $gittime &&
 		test $p4time = $gittime
 	)