do not run pager with diff --no-index --quiet

There is no point in running a pager when --quiet is given,
since we are producing no output. The regular diff code path
handles this already, because --quiet implies --exit-code,
and we check for --exit-code when deciding not to run the
pager.

However, the "quiet implies exit-code" logic is done in
diff_setup_done, and the no-index code path sets up its
pager before running diff_setup_done, and misses this case.

We can fix this by reordering our initialization.
Currently we do:

  1. read command line arguments into diff_options

  2. Set pager if EXIT_CODE not requested

  3. always set EXIT_CODE, since we are emulating
     traditional diff

  4. call diff_setup_done

We can fix the problem by moving pager initialization (step
2) after step 4. But step 3 must come after step 2 (since we
want to know whether the _user_ requested --exit-code, not
whether we turned it on unconditionally). So we must move
both.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff-no-index.c

@@ -224,8 +224,6 @@ void diff_no_index(struct rev_info *revs,
 		}
 	}
 
-	setup_diff_pager(&revs->diffopt);
-
 	if (prefix) {
 		int len = strlen(prefix);
 		const char *paths[3];
@@ -250,13 +248,15 @@ void diff_no_index(struct rev_info *revs,
 	if (!revs->diffopt.output_format)
 		revs->diffopt.output_format = DIFF_FORMAT_PATCH;
 
-	DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
 	DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
 
 	revs->max_count = -2;
 	if (diff_setup_done(&revs->diffopt) < 0)
 		die("diff_setup_done failed");
 
+	setup_diff_pager(&revs->diffopt);
+	DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
+
 	if (queue_diff(&revs->diffopt, revs->diffopt.pathspec.raw[0],
 		       revs->diffopt.pathspec.raw[1]))
 		exit(1);