make: Add generation of cpt2 version

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Print version on -V option

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
.gitignore: Add version.h here

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>