Add a pointer to the primary context of a connection and use it in all
driver functions that don't dependent on the context type. This includes
almost all functions that deal with a virDomianPtr. Therefore, using
a vpx:// connection allows you to perform all the usual domain related
actions like start, destroy, suspend, resume, dumpxml etc.
Some functions that require an explicitly specified ESX server don't work
yet. This includes the host UUID, the hostname, the general node info, the
max vCPU count and the free memory. Also not working yet are migration and
defining new domains.
Also define ESX_ERROR and ESX_VI_ERROR in a central place, instead of
defining them in each source file.
Add ESX_ERROR and ESX_VI_ERROR to the msg_gen_function list in cfg.mk.
Update po/POTFILES.in accordingly.