Declare safe_read static.

This appears to be the intention, and the name collides with
various routines.

Signed-off-by: Matt Benjamin <matt@linuxbox.com>
Restore static build.

Rather than adding new constructor routines, use xio_init() like
module_init.

Signed-off-by: Matt Benjamin <matt@linuxbox.com>
moving destructor into xio_shutdown

Signed-off-by: Eyal Salomon <esalomon@mellanox.com>