Deploy also platforminputcontext plugins

This is required at least with Qt 5.1 / Linux.

Task-number: QTCREATORBUG-8471
Change-Id: I7342193ef40fcc1a3e523d787c7521d6e810cd61
Reviewed-by: Gatis Paeglis <gatis.paeglis@digia.com>
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>