clipboard fix clipboard tracking when clip and primary are synced
clipboard fix clipboard tracking when clip and primary are synced

Previously, if primary didn't affect history, the clipboard owner changed
would be dismissed if we explicitely copied some stuff, so nothing was ever
added to the history.

fixes #170

Signed-off-by: Marc-Antoine Perennou <07f76cf0511c79b361712839686f3cee8c75791c@Perennou.com>

Keruspe/GPaste,Keruspe/GPaste,Keruspe/GPaste