Correctly re-initialize signal handlers on RESTART

This fixes part 2 of bug #127 :-)

src/ngircd/ngircd.c

@@ -330,6 +330,7 @@ main(int argc, const char *argv[])
 		Channel_Exit();
 		Class_Exit();
 		Log_Exit();
+		Signals_Exit();
 	}
 	Pidfile_Delete();
 

src/ngircd/sighandlers.c

@@ -334,6 +334,7 @@ Signals_Exit(void)
 #endif
 	close(signalpipe[1]);
 	close(signalpipe[0]);
+	signalpipe[0] = signalpipe[1] = 0;
 }
 
 /* -eof- */