chg: ignore SIGINT while waiting pager termination

Otherwise the terminal would be left with unclean state. This is what
fcc4b55876c3 does.

contrib/chg/chg.c

@@ -434,8 +434,6 b' static void restoresignalhandler()'
 
 	if (sigaction(SIGHUP, &sa, NULL) < 0)
 		goto error;
-	if (sigaction(SIGINT, &sa, NULL) < 0)
-		goto error;
 	if (sigaction(SIGTERM, &sa, NULL) < 0)
 		goto error;
 	if (sigaction(SIGWINCH, &sa, NULL) < 0)
@@ -445,6 +443,11 b' static void restoresignalhandler()'
 	if (sigaction(SIGTSTP, &sa, NULL) < 0)
 		goto error;
 
+	/* ignore Ctrl+C while shutting down to make pager exits cleanly */
+	sa.sa_handler = SIG_IGN;
+	if (sigaction(SIGINT, &sa, NULL) < 0)
+		goto error;
+
 	peerpid = 0;
 	return;