InstanceMappingList.get_by_cell_and_project() is being changed to
get_not_deleted_by_cell_and_project() by which we change the method to
filter out not queued_for_delete instance_mappings and also for
the method to accept cell_uuid as the input instead of the cell_id.
This also adds an optional limit parameter. This is more useful than
the ealier approach since it would increase the performance slightly
by not having to query for the cell_mappings explicitly to get the
cell ids from the cell uuids obtained from scatter gather utility.
Note that this method was added relatively recently and hence is not
used anywhere which is why it should be fine to change this, keeping
in mind the intention of having added it in the first place.
Change-Id: I5df9851cce0b6e635c74fd34f5be9c4906dd7406
Related to blueprint handling-down-cell
d4f8040117