Bug 1636: Config Netconf Connector did not serialize service type

Config Netconf connector did not serialized service type
in list of service dependencies properly, which resulted
in invalid string 'prefix:null'

Change-Id: I02cc56e2069b56737167d9b694f8cb8309bbd74d
Signed-off-by: Tony Tkacik <ttkacik@cisco.com>
Merge "Bug 1636: Config Netconf Connector did not serialize service type"