manager-serialize: add logging for ENOMEM

src/core/manager-serialize.c

@@ -199,13 +199,13 @@ static int manager_deserialize_one_unit(Manager *m, const char *name, FILE *f, F
 
         r = manager_load_unit(m, name, NULL, NULL, &u);
         if (r == -ENOMEM)
-                return r;
+                return log_oom();
         if (r < 0)
                 return log_notice_errno(r, "Failed to load unit \"%s\", skipping deserialization: %m", name);
 
         r = unit_deserialize_state(u, f, fds);
         if (r == -ENOMEM)
-                return r;
+                return log_oom();
         if (r < 0)
                 return log_notice_errno(r, "Failed to deserialize unit \"%s\", skipping: %m", name);