Fix the memory protection issue in RosAllocSpace::CreateFromMemMap()

From the implementation of RosAllocSpace::CreateFromMemMap(), the memory
beyond the starting_size should be protected.
But the argument of mprotect is wrongly set to be "capacity -
initial_size", logically it should be "capacity - starting_size"
This patch also fix the same issue in dlmalloc

Change-Id: Icbd4ba790f344d4fa79d9896657f638a03d6f8aa
Author: Lin Zang <lin.zang@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>