CA-141364: Remove wasted hypercalls on domain build

The HPET and VPT are enabled or otherwise within Xenguest. Doing so here is
unnecessary.

Also, at the time of writing, the binding for VPT alignment is
setting the HPET again by mistake:

https://github.com/xapi-project/xen-api-libs-transitional/blob/d6cf85fd/xenctrlext/xenctrlext_stubs.c#L128-L135

These will be removed.

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CA-141364: Don't ignore errors from libxc on domain build

Failures from these calls are fatal and we should not continue with any VM
build (start, resume) operations if these calls return an error.

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
CA-141364: Remove redundant (and erroneous bindings)

We no longer need these bindings since this work is done in Xenguest. Also, it
appears both of the bindings mistakenly make the same call into libxc.

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
Merge pull request #103 from simonjbeaumont/ca-141364

CA-141364: Handle errors during domain build