Set default service type to 'management'
Set default service type to 'management'

We don't know yet what service type will be used in Keystone to
identify Tuskar service, but it sure won't be 'metering'. We should
rather get an unknown service type error than fetch a Ceilometer
service URL mistakenly.

rdo-management/python-tuskarclient,tuskar/python-tuskarclient