First, we don't need to call prlsdkApplyConfig after
creating new VM or containers, because it's done in
functions prlsdkCreateVm and prlsdkCreateCt.

No need to check, if domain exists in the list after
prlsdkAddDomain.

Also organize code, so that we can call virObjectUnlock
in one place.
Signed-off-by: NDmitry Guryanov <dguryanov@parallels.com>