eseries.py: Remove access_group_delete
eseries.py: Remove access_group_delete

1. The call to self._get_class_instance is incorrect
2. The base smi-s plugin doesn't support this functionality
3. The eseries plugin doesn't allow you to create a plugin, so
   difficult to test

Signed-off-by: Tony Asleson <1ef2d381aa56d512126ddaacc29e68136e4fdf55@redhat.com>

jumitche/libstoragemgmt,cathay4t/libstoragemgmt,joehandzik/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,libstorage/libstoragemgmt,joehandzik/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,tasleson/libstoragemgmt,libstorage/libstoragemgmt,tasleson/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,cathay4t/libstoragemgmt,cathay4t/libstoragemgmt,jumitche/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,joehandzik/libstoragemgmt,libstorage/libstoragemgmt,jumitche/libstoragemgmt,tasleson/libstoragemgmt,lazy404/libstoragemgmt,tasleson/libstoragemgmt,libstorage/libstoragemgmt,jumitche/libstoragemgmt,libstorage/libstoragemgmt,cathay4t/libstoragemgmt,jumitche/libstoragemgmt,cathay4t/libstoragemgmt,joehandzik/libstoragemgmt,tasleson/libstoragemgmt,lazy404/libstoragemgmt,lazy404/libstoragemgmt,lazy404/libstoragemgmt