status: reduce duplicated setup code

We have three output formats: short, porcelain, and long.
The short and long formats respect user-config, and the
porcelain one does not. This led to us repeating
config-related setup code for the short and long formats.

Since the last commit, color config is explicitly cleared
when showing the porcelain format. Let's do the same with
relative-path configuration, which enables us to hoist the
duplicated code from the switch statement in cmd_status.

As a bonus, this fixes "commit --dry-run --porcelain", which
was unconditionally setting up that configuration, anyway.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

builtin-commit.c

@@ -964,14 +964,15 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 	s.is_initial = get_sha1(s.reference, sha1) ? 1 : 0;
 	wt_status_collect(&s);
 
+	if (s.relative_paths)
+		s.prefix = prefix;
+	if (s.use_color == -1)
+		s.use_color = git_use_color_default;
+	if (diff_use_color_default == -1)
+		diff_use_color_default = git_use_color_default;
+
 	switch (status_format) {
 	case STATUS_FORMAT_SHORT:
-		if (s.relative_paths)
-			s.prefix = prefix;
-		if (s.use_color == -1)
-			s.use_color = git_use_color_default;
-		if (diff_use_color_default == -1)
-			diff_use_color_default = git_use_color_default;
 		wt_shortstatus_print(&s, null_termination);
 		break;
 	case STATUS_FORMAT_PORCELAIN:
@@ -979,12 +980,6 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 		break;
 	case STATUS_FORMAT_LONG:
 		s.verbose = verbose;
-		if (s.relative_paths)
-			s.prefix = prefix;
-		if (s.use_color == -1)
-			s.use_color = git_use_color_default;
-		if (diff_use_color_default == -1)
-			diff_use_color_default = git_use_color_default;
 		wt_status_print(&s);
 		break;
 	}

wt-status.c

@@ -692,5 +692,7 @@ void wt_shortstatus_print(struct wt_status *s, int null_termination)
 void wt_porcelain_print(struct wt_status *s, int null_termination)
 {
 	s->use_color = 0;
+	s->relative_paths = 0;
+	s->prefix = NULL;
 	wt_shortstatus_print(s, null_termination);
 }