tls_schannel: don't force RC4 for TLS handshake

Leave default configuration. A particular server closes tcp connection
during negotiation otherwise.

tls_schannel is still broken and tls_read() fails with
SEC_E_UNSUPPORTED_FUNCTION error.

src/tls_schannel.c

@@ -125,10 +125,16 @@ tls_t *tls_new(xmpp_ctx_t *ctx, sock_t sock)
     memset(&scred, 0, sizeof(scred));
     scred.dwVersion = SCHANNEL_CRED_VERSION;
     /*scred.grbitEnabledProtocols = SP_PROT_TLS1_CLIENT;*/
+    /* Remote server closes connection with forced RC4.
+       The below lines are commented to leave default system configuration */
+#if 0
     /* Something down the line doesn't like AES, so force it to RC4 */
     algs[0] = CALG_RC4;
     scred.cSupportedAlgs = 1;
     scred.palgSupportedAlgs = algs;
+#else
+    (void)algs;
+#endif
 
     ret = tls->sft->AcquireCredentialsHandleA(NULL, UNISP_NAME,
 	SECPKG_CRED_OUTBOUND, NULL, &scred, NULL, NULL, &(tls->hcred), NULL);
@@ -354,6 +360,7 @@ int tls_start(tls_t *tls)
 
     if (ret != SEC_E_OK) {
 	tls->lasterror = ret;
+	xmpp_error(tls->ctx, "TLSS", "Schannel error 0x%lx", (unsigned long)ret);
 	return 0;
     }