Errors from AmPath topology validation

[sajith]

Similar to #85, came across this too while working on #62:

>>> from sdx.datamodel.parsing.topologyhandler import TopologyHandler
>>> from sdx.datamodel.validation.topologyvalidator import TopologyValidator
>>> topology = TopologyHandler().import_topology("tests/data/ampath.json")
>>> validator = TopologyValidator()
>>> validator.set_topology(topology)
>>> validator.is_valid()
Global Institution must be in Topology urn:sdx:topology:
Location location Address must exist
Link urn:sdx:link::Ampath5/177_JAX/249 Port {'id': 'urn:sdx:port::Ampath5:177'} should be a string or a dict. Not dict
Link urn:sdx:link::Ampath5/177_JAX/249 Port {'id': 'urn:sdx:port::JAX:249'} should be a string or a dict. Not dict
False

Unsure if this is because of wrong assumptions or wrong input.