log: make tools also read the kernel command line when run as a service

This effectively reverts 41d1f469cf.

Before this, e.g., `networkctl reload` invoked by `systemctl reload systemd-networkd.service`
does not produce debugging logs even if systemd.log-level=debug is set. This fixes
the issue.

src/systemctl/systemctl.c

@@ -1085,7 +1085,7 @@ static int run(int argc, char *argv[]) {
         int r;
 
         setlocale(LC_ALL, "");
-        log_parse_environment_cli();
+        log_parse_environment();
         log_open();
 
         /* The journal merging logic potentially needs a lot of fds. */