Fix the broken pipe error in client connection


I found that during running the integration test, it is very possibly that the two tests `TestHttpsInfoRogueCert` and `TestHttpsInfoRogueServerCert` would cause broken pipe error and interrupt the whole test.

The pipe signal is due to the http server finds TLS handshake error and closes the connection while the client is still sending data. Based on the timing different in each individual connecting, the signal sometimes happens and sometimes not.

This PR tries to deal with this problem by adding a signal handler for the pipe signal.