lsa: increase segment size
lsa: increase segment size

While #152 is still open, we need to allow for moderately sized allocations
to succeed.  Extend the segment size to 256k, which allows for threads to
be allocated.

Fixes #151.

eklitzke/scylla,wildinto/scylla,bowlofstew/scylla,wildinto/scylla,bowlofstew/scylla,gwicke/scylla,duarten/scylla,capturePointer/scylla,glommer/scylla,capturePointer/scylla,scylladb/scylla,scylladb/scylla,aruanruan/scylla,capturePointer/scylla,raphaelsc/scylla,respu/scylla,avikivity/scylla,bowlofstew/scylla,senseb/scylla,dwdm/scylla,kjniemi/scylla,rentongzhang/scylla,phonkee/scylla,phonkee/scylla,duarten/scylla,victorbriz/scylla,kangkot/scylla,kangkot/scylla,wildinto/scylla,senseb/scylla,justintung/scylla,rluta/scylla,justintung/scylla,asias/scylla,tempbottle/scylla,guiquanz/scylla,dwdm/scylla,rentongzhang/scylla,kjniemi/scylla,kangkot/scylla,asias/scylla,aruanruan/scylla,dwdm/scylla,victorbriz/scylla,rentongzhang/scylla,gwicke/scylla,raphaelsc/scylla,rluta/scylla,scylladb/scylla,eklitzke/scylla,acbellini/scylla,guiquanz/scylla,avikivity/scylla,eklitzke/scylla,stamhe/scylla,stamhe/scylla,justintung/scylla,respu/scylla,victorbriz/scylla,guiquanz/scylla,scylladb/scylla,gwicke/scylla,linearregression/scylla,linearregression/scylla,linearregression/scylla,acbellini/scylla,asias/scylla,glommer/scylla,shaunstanislaus/scylla,raphaelsc/scylla,respu/scylla,kjniemi/scylla,stamhe/scylla,phonkee/scylla,tempbottle/scylla,shaunstanislaus/scylla,acbellini/scylla,aruanruan/scylla,glommer/scylla,shaunstanislaus/scylla,avikivity/scylla,tempbottle/scylla,duarten/scylla,senseb/scylla,rluta/scylla