Adding first page to collection via json not to alert (Bug 1369343)

When adding the first page to a collection via drag/drop the alert
pops up saying you are change page permissions - but that isn't true.

Change-Id: Icacbd3c131e13bb216eba0d8a15de000b702686c
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>