CMFileManager : Switch to checked states

Selected states are not being tracked properly when rotated.

Repro:

1. Click to open file
2. Tap on first item in resolver dialog
3. Rotate device
4. Press ok
5. Enjoy crash

issue-id: CYNGNOS-991

Change-Id: I9ef5d0571201957eac40edc8bc5e47700752dcc3