Android: fix setting camera parameters from QML.

We were ignoring new parameter values when the camera was not loaded.
All QML properties that were set at initialization time were therefore
ignored since the camera is not loaded at that point.
We now store all camera parameters and apply them once the camera is
loaded.

Task-number: QTBUG-39307
Change-Id: If66d768941c25cede2aea1b48fb928c4735c10f8
Reviewed-by: Christian Stromme <christian.stromme@digia.com>