tmpfiles: fix L+ to replace non-directory entries

The L+ type should replace existing entries with a symlink. Previously,
rmrf() was always called which is only appropriate for directories.
Now we check if the path is a directory first, and use erase() for
files and symlinks.

src/tmpfiles.c

@@ -568,7 +568,10 @@ static void tmpfiles(char *line)
 			if (!strc) {
 				if (type[1] != '+')
 					break;
-				rmrf(path);
+				if (fisdir(path))
+					rmrf(path);
+				else
+					erase(path);
 			}
 			mkparent(path, 0755);
 			if (!arg) {