vspace_mmu_aware: fixed edge case in assertions.
vspace_mmu_aware: fixed edge case in assertions.

Assertions didn't allow freeing the region starting at offset zero in the
vregion.

Signed-off-by: Simon Gerber <13ba2e9de9ead0ea0b5f47504fb3a80bb9b1ee3b@hp.com>

BarrelfishOS/barrelfish,8l/barrelfish,BarrelfishOS/barrelfish,BarrelfishOS/barrelfish,kishoredbn/barrelfish,kishoredbn/barrelfish,8l/barrelfish,8l/barrelfish,8l/barrelfish,BarrelfishOS/barrelfish,kishoredbn/barrelfish,BarrelfishOS/barrelfish,8l/barrelfish,BarrelfishOS/barrelfish,kishoredbn/barrelfish,8l/barrelfish,BarrelfishOS/barrelfish,kishoredbn/barrelfish,BarrelfishOS/barrelfish,kishoredbn/barrelfish,BarrelfishOS/barrelfish