esx_vi_generator: Simplify get_occurrence_comment
esx_vi_generator: Simplify get_occurrence_comment

Reduce the number of if-statements and use a single return.
Utilise a dictionary to map between occurrences and values.

Reviewed-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>
Signed-off-by: Radostin Stoyanov <31e0ffafc95759db9487554f968b40977ab67b6b@gmail.com>

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