esx: Report error in esxVI_LookupVirtualMachineByName
esx: Report error in esxVI_LookupVirtualMachineByName

When reviewing 00d9edfe2f39f60b40 I've changed proposed patch and
made it to not report error if no domain is found. This is wrong
and the original patch was okay. Thing is, both callers pass
occurrence = OptionalItem so no error message overwriting is done
as I thought initially.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>

eskultety/libvirt,eskultety/libvirt,nertpinx/libvirt,crobinso/libvirt,crobinso/libvirt,jardasgit/libvirt,eskultety/libvirt,jardasgit/libvirt,jardasgit/libvirt,jfehlig/libvirt,libvirt/libvirt,zippy2/libvirt,zippy2/libvirt,libvirt/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,libvirt/libvirt,fabianfreyer/libvirt,olafhering/libvirt,libvirt/libvirt,olafhering/libvirt,nertpinx/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,jfehlig/libvirt,nertpinx/libvirt,olafhering/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,nertpinx/libvirt,jfehlig/libvirt,eskultety/libvirt,fabianfreyer/libvirt,eskultety/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,crobinso/libvirt,crobinso/libvirt,jfehlig/libvirt,zippy2/libvirt,zippy2/libvirt,jardasgit/libvirt,olafhering/libvirt,nertpinx/libvirt