index manager role does not allow user to create indexes

For a bucket with a password, create a user with query_index_manager authority:

curl -X PUT http://localhost:8091/settings/rbac/users/builtin/idxmanage -d "name=Idx Manage&roles=query_manage_index[bucket1]&password=pwidxmanage" -u Administrator:password

Then attempt to create an index with that user:

curl http://localhost:8093/query/service -d "statement=create index idx1 on bucket1(foo)" -u idxmanage:pwidxmanage

This should succeed, but it fails.

Tested with build 2217. Test #10 in suite: https://docs.google.com/document/d/1RBQAKMhfXdm-4dAF5xyNJDbcNrRcRnfDcCRYKAQSvtc/edit