Comment 8 for bug 952964

The attached patch fixes the Scroll issue in Remmina.

The patch implements the GDK_SCROLL_SMOOTH event.
Which was just ignored before. (Only GDK_SCROLL_UP/DOWN was used).

This exact same code has also been added upstream:
https://github.com/FreeRDP/Remmina/commit/1aebfc027507607d5f061ba9072eb952e07214d1

Which means next Remmina release we can drop this patch.