Gallery2: fix selection count didn't update after folder is deleted

If we select an album and then delete it in file explorer, the
Gallery2 can not update the selection count, we change to
leave selection mode when albumsetpage is paused.

CRs-Fixed: 529042

Change-Id: Ic972ea23a64e0779e18ca9397b4619fb90ce3ecf
Merge "Gallery2: fix selection count didn't update after folder is deleted" into du44