Compile Xe command with dynamic linking

It was the last executable compiled with static linking.

Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Add pool_role_shared to rdd-client library.

This library use this module to add it to the library.
This is clearly detected by new CentOS 6.4 rpm tool which is able to
understand Ocaml library relationship inside rpms.

Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Merge pull request #1345 from freddy77/build_fixes

Build fixes