Use 0px radius in GtkToolButton prelight state
Use 0px radius in GtkToolButton prelight state

Signed-off-by: Agustin Zubiaga <4debfd70428c733f74c86553e9d39f7d8492aaa9@sugarlabs.org>
Acked-by: Manuel Quiñones <6f5069c5b6be23302a13accec56587944be09079@laptop.org>
Signed-off-by: Ajay Garg <1c58a446a63e719d7b90156a8998ccc461609ed7@activitycentral.com>

ceibal-tatu/sugar-artwork,ceibal-tatu/sugar-artwork,ceibal-tatu/sugar-artwork