tree-wide: when %m is used in log_*, always specify errno explicitly

All those uses were correct, but I think it's better to be explicit.
Using implicit errno is too error prone, and with this change we can require
(in the sense of a style guideline) that the code is always specified.

Helpful query: git grep -n -P 'log_[^s][a-z]+\(.*%m'

src/libudev/libudev-monitor.c

@@ -681,7 +681,7 @@ retry:
 
         udev_device = udev_device_new_from_nulstr(udev_monitor->udev, &buf.raw[bufpos], buflen - bufpos);
         if (!udev_device) {
-                log_debug("could not create device: %m");
+                log_debug_errno(errno, "could not create device: %m");
                 return NULL;
         }