Fix dropped SSL connection when send buffer runs full.

Author: everslick

libraries/WiFiClientSecure/src/ssl_client.cpp

@@ -241,17 +241,14 @@ int data_to_read(sslclient_context *ssl_client)
 
 int send_ssl_data(sslclient_context *ssl_client, const uint8_t *data, uint16_t len)
 {
-    log_v("Writing HTTP request...");  //for low level debug
     int ret = -1;
 
     while ((ret = mbedtls_ssl_write(&ssl_client->ssl_ctx, data, len)) <= 0) {
-        if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
+        if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE && ret < 0) {
             return handle_error(ret);
         }
     }
 
-    len = ret;
-    //log_v("%d bytes written", len);  //for low level debug
     return ret;
 }