Enable del of other tenants resources by name

Currently, due to the way that resources are being retrieved by the
findall() function, an administrator can do a list, snapshot-list, etc.
with the --all_tenants option and see other tenants' resources.  If the
admin then tries to delete the another tenants' resource by name, it fails
with a 'No <resource> with a name or ID of <name> exists.' error.

The solution to this is to change the call to the list() function in
findall() to set the all_tenants search option to 1.  This causes the
admin to get a list of all the resources that they have access to back
when the search is done instead of just a list of their resources.  The
delete by name is then possible.  The server takes care of ensuring that
only resources that the user has access to are returned.

This will enable delete by name for all resources that use the find_resource
function.

Closes-bug: 1241682
Change-Id: I4e9957b66c11b7e1081f066d189cedc5a3cb2a6c
Merge "Enable del of other tenants resources by name"