Originally, `systemctl cat` would match only active units, for example:
$ systemctl cat sshd.service
would cat the sshd.service unit file even if the service was inactive.
However:
$ systemctl cat ssh*
would show it only if it was active.
Let's unify the behavior and cat all unit files regardless of a state,
if no state was given explicitly to filter.
bool first = true;
int r;
+ /* Include all units by default - i.e. continue as if the --all
+ * option was used */
+ if (strv_isempty(arg_states))
+ arg_all = true;
+
if (arg_transport != BUS_TRANSPORT_LOCAL)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Cannot remotely cat units.");