Migration now accepts scope as argument
Adds a new option to command ipa migrate-ds, --scope=[base,onelevel,subtree]
which allows the user to specify LDAP search depth for users and groups.
'onelevel' was the hard-coded level before this patch and is still
default. Specify 'subtree' to search nested OUs for users and groups.
https://fedorahosted.org/freeipa/ticket/2547
Reviewed-By: Martin Basti <mbasti@redhat.com>