treewide: apply errno.cocci

with small manual cleanups for style.

src/machine/machined.c

@@ -150,8 +150,7 @@ int manager_enumerate_machines(Manager *m) {
                 if (errno == ENOENT)
                         return 0;
 
-                log_error_errno(errno, "Failed to open /run/systemd/machines: %m");
-                return -errno;
+                return log_error_errno(errno, "Failed to open /run/systemd/machines: %m");
         }
 
         FOREACH_DIRENT(de, d, return -errno) {