A GNUTLS_E_PREMATURE_TERMINATION during TLS handshake doesn't result in a  G_TLS_ERROR_NOT_TLS being returned. (Results in libsoup not retrying to connect)

Test URL: https://accounts.craigslist.org

Basic fix:

diff --git a/tls/gnutls/gtlsconnection-gnutls.c b/tls/gnutls/gtlsconnection-gnutls.c
index ccdb59c..a811de7 100644
--- a/tls/gnutls/gtlsconnection-gnutls.c
+++ b/tls/gnutls/gtlsconnection-gnutls.c
@@ -694,6 +694,9 @@ end_gnutls_io (GTlsConnectionGnutls  *gnutls,
 	  status == GNUTLS_E_UNEXPECTED_PACKET_LENGTH ||
 	  status == GNUTLS_E_FATAL_ALERT_RECEIVED ||
 	  status == GNUTLS_E_DECRYPTION_FAILED ||
+#ifdef GNUTLS_E_PREMATURE_TERMINATION
+	  status == GNUTLS_E_PREMATURE_TERMINATION ||
+#endif
 	  status == GNUTLS_E_UNSUPPORTED_VERSION_PACKET)
 	{
 	  g_clear_error (&my_error);