esxVI_WaitForTaskCompletion can take a UUID to lookup the
corresponding domain and check if the current task for it
is blocked by a question. It calls another function to do
this: esxVI_LookupAndHandleVirtualMachineQuestion looks up
the VirtualMachine and checks for a question. If there is
a question it calls esxVI_HandleVirtualMachineQuestion to
handle it.

If there was no question or it has been answered the call
to esxVI_LookupAndHandleVirtualMachineQuestion returns 0.
If any error occurred during the lookup and answering
process -1 is returned. The problem with this is, that -1
is also returned when there was no error but the question
could not be answered. So esxVI_WaitForTaskCompletion cannot
distinguish between this two situations and reports that a
question is blocking the task even when there was actually
another problem.

This inherent problem didn't surface until vSphere 4.1 when
you try to define a new domain. The driver tries to lookup
the domain that is just in the process of being registered.
There seems to be some kind of race condition and the driver
manages to issue a lookup command before the ESX server was
able to register the domain. This used to work before.

Due to the return value problem described above the driver
reported a false error message in that case.

To solve this esxVI_WaitForTaskCompletion now takes an
additional occurrence parameter that describes whether or
not to expect the domain to be existent. Also add a new
parameter to esxVI_LookupAndHandleVirtualMachineQuestion
that allows to distinguish if the call returned -1 because
of an actual error or because the question could not be
answered.