logger: fix error handling

TODO

@@ -69,6 +69,8 @@
 
 * isolate multi-user.target doesn't start a getty@tty1 if we run it from graphical.target
 
+* alsa rule file, alsa service files, alsa state file → /var/lib, sequencer soll by device node ladbar
+
 Fedora:
 
 * obsolete readhead in system pkgs

src/logger.c

@@ -318,7 +318,7 @@ static int stream_process(Stream *s, usec_t ts) {
                         return 0;
 
                 log_warning("Failed to read from stream: %m");
-                return -1;
+                return -errno;
         }