tcpd: waitpid() for any child process

. prevents zombies from accumulating for as long as tcpd exists
	  for child processes that create their own process group, e.g. ftpd.

Change-Id: Ic56597810f7d17e1cc28b755e2d1998ecf49a27c

commands/tcpd/tcpd.c

@@ -40,7 +40,7 @@ static void report(const char *label)
 
 static void sigchld(int sig)
 {
-    while (waitpid(0, NULL, WNOHANG) > 0) {
+    while (waitpid(-1, NULL, WNOHANG) > 0) {
 	if (nchildren > 0) nchildren--;
     }
 }