Merge pull request #195 from djs55/new-xapi2

Update xapi to 1.9.23
Another xapi

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #196 from djs55/moremore

Another xapi
Update xapi with migration hack

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #197 from djs55/hack

Update xapi with migration hack
Merge branch 'build-improvements' of github.com:euanh/xen-api-rpm-buildroot into build-improvements