fast-import: Cleanup mode setting.

"S_IFREG | mode" makes only sense for 0644 and 0755.

Even though doing (S_IFREG | mode) may not hurt when mode is any other
supported value, that is only true because S_IFREG mode bit happens to
be already on for S_IFLNK or S_IFGITLINK.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Acked-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fast-import.c

@@ -1868,12 +1868,13 @@ static void file_change_m(struct branch *b)
 	if (!p)
 		die("Corrupt mode: %s", command_buf.buf);
 	switch (mode) {
+	case 0644:
+	case 0755:
+		mode |= S_IFREG;
 	case S_IFREG | 0644:
 	case S_IFREG | 0755:
 	case S_IFLNK:
 	case S_IFGITLINK:
-	case 0644:
-	case 0755:
 		/* ok */
 		break;
 	default:
@@ -1940,7 +1941,7 @@ static void file_change_m(struct branch *b)
 			    typename(type), command_buf.buf);
 	}
 
-	tree_content_set(&b->branch_tree, p, sha1, S_IFREG | mode, NULL);
+	tree_content_set(&b->branch_tree, p, sha1, mode, NULL);
 }
 
 static void file_change_d(struct branch *b)