ceph: Move page.{cc,h} files to sysconf.{cc.h}

Signed-off-by: Christophe Courtaut <christophe.courtaut@gmail.com>
ceph: Do not use IOV_MAX. use sysconf instead.

Signed-off-by: Christophe Courtaut <christophe.courtaut@gmail.com>
ceph: Do not rely on PATH_MAX. use pathconf instead.

Signed-off-by: Christophe Courtaut <christophe.courtaut@gmail.com>