Fix Botan leaking memory if connection force closed (#300)

Author: marty1885

trantor/net/inner/TcpConnectionImpl.cc

@@ -439,6 +439,9 @@ void TcpConnectionImpl::forceClose()
         {
             thisPtr->status_ = ConnStatus::Disconnecting;
             thisPtr->handleClose();
+
+            if (thisPtr->tlsProviderPtr_)
+                thisPtr->tlsProviderPtr_->close();
         }
     });
 }

trantor/net/inner/tlsprovider/BotanTLSProvider.cc

@@ -229,7 +229,10 @@ struct BotanTLSProvider : public TLSProvider,
     virtual void close() override
     {
         if (channel_ && channel_->is_active())
+        {
             channel_->close();
+            channel_ = nullptr;
+        }
     }
 
     virtual void startEncryption() override