Gallery2: keep selection mode when deSelectAll

Origin code will call leaveSelectionMode function in
deSelectAll and will not keep in selected status on
this situation.

Add DESELECT_ALL_MODE in AlbumPage and
AlbumSetPage to make stay in selection mode even if
choose deSelectAll.

CRs-Fixed: 342469

Change-Id: Ia8819ba197444c33b1641ad33dd8602ecca0075c
Merge "Gallery2: keep selection mode when deSelectAll" into du44