Tests: proxy_store leaving temporary files bug test.

It shouldn't even if client closed prematurely connection.
diff --git a/lib/Test/Nginx.pm b/lib/Test/Nginx.pm
index ed2da14..5986468 100644
--- a/lib/Test/Nginx.pm
+++ b/lib/Test/Nginx.pm
@@ -260,6 +260,7 @@
 		$s->print($request);
 		local $/;
 		select undef, undef, undef, $extra{sleep} if $extra{sleep};
+		return '' if $extra{aborted};
 		$reply = $s->getline();
 		log_in($reply);
 		alarm(0);