Increase memory alignment for slotmem data in

mod_slotmem_shm.

Consumers still need to choose the slot sizes
appropriate for consistent alignment.
mod_slotmem_shm only cares about the alignment
for the first slot.

We use the APR default alignment.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1060108 13f79535-47bb-0310-9956-ffa450edef68