esx: Fix error reporting in esxVI_LookupManagedObjectHelper
esx: Fix error reporting in esxVI_LookupManagedObjectHelper

As the name parameter can be NULL the error message can only contain it
conditionally.

fabianfreyer/libvirt,zippy2/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,olafhering/libvirt,rlaager/libvirt,crobinso/libvirt,agx/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,jfehlig/libvirt,libvirt/libvirt,nertpinx/libvirt,nertpinx/libvirt,zhlcindy/libvirt-1.1.4-maintain,elmarco/libvirt,jfehlig/libvirt,libvirt/libvirt,jardasgit/libvirt,cbosdo/libvirt,eskultety/libvirt,taget/libvirt,zippy2/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,datto/libvirt,olafhering/libvirt,fabianfreyer/libvirt,agx/libvirt,cbosdo/libvirt,datto/libvirt,zippy2/libvirt,libvirt/libvirt,zhlcindy/libvirt-1.1.4-maintain,andreabolognani/libvirt,VenkatDatta/libvirt,datto/libvirt,datto/libvirt,nertpinx/libvirt,jfehlig/libvirt,agx/libvirt,rlaager/libvirt,eskultety/libvirt,zippy2/libvirt,shugaoye/libvirt,taget/libvirt,fabianfreyer/libvirt,cbosdo/libvirt,shugaoye/libvirt,andreabolognani/libvirt,eskultety/libvirt,andreabolognani/libvirt,agx/libvirt,shugaoye/libvirt,cbosdo/libvirt,elmarco/libvirt,rlaager/libvirt,rlaager/libvirt,zhlcindy/libvirt-1.1.4-maintain,shugaoye/libvirt,olafhering/libvirt,elmarco/libvirt,VenkatDatta/libvirt,taget/libvirt,jardasgit/libvirt,elmarco/libvirt,taget/libvirt,crobinso/libvirt,olafhering/libvirt,shugaoye/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,nertpinx/libvirt,zhlcindy/libvirt-1.1.4-maintain,rlaager/libvirt,cbosdo/libvirt,agx/libvirt,eskultety/libvirt,elmarco/libvirt,zhlcindy/libvirt-1.1.4-maintain,datto/libvirt,libvirt/libvirt,eskultety/libvirt,jardasgit/libvirt,crobinso/libvirt,jardasgit/libvirt,crobinso/libvirt,taget/libvirt