A WebProcess crash issue by confusion of widget handle after DynamicBox re-installation.

A WebProcess crash issue by confusion of widget handle after DynamicBox re-installation.

[Issue#]   PLM-131009-03049
[Problem]  Make a DynamicBox is located in homescreen and if try to update its package by
           re-installation, a WebProcess crash occurs.
[Cause]    When a DynamicBox is updated, web-provider re-uses WebProcess which was used by
           previous one. So then the widget handle is updated, but plugin-logic couldn't know that.
           Because wrt plugin-logic was not been considered about such reuse case.
           So, there was a problem on accessing widget handle which is internal variable of singleton.
[Solution] Fixed the wrt plugin-logic to update internal variable of singleton properly even in that case.

Change-Id: I0ecde7906b941778ee9027914d7a695aad59c036