libxl: remove usage of virDomainJobData

libxl: remove usage of virDomainJobData

Struct virDomainJobData is meant for statistics for async jobs.
It was used to keep track of only two attributes, one of which is
also in the generalized virDomainJobObj ("started") and one which
is always set to the same value, if any job is active
("jobType").

This patch removes usage & allocation of virDomainJobData
structure and rewrites libxlDomainJobUpdateTime() into more
suitable libxlDomainJobGetTimeElapsed().

Signed-off-by: Kristina Hanicova <khanicov@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>