Explainer wrapper should not add model to path for Tensorflow protocol

[ukclivecox]

The issue is the model name may not equal the model name loaded by tenorflow serving which is based on the name of the graph element. Explanations are at a predictor level so should just call predict and not focus on any particular model.

seldon-core/components/alibi-explain-server/alibiexplainer/explainer.py

Line 46 in f48d5b3

KFSERVING_PREDICTOR_URL_FORMAT = "http://{0}/v1/models/{1}:predict"

Should remove {1}

This is ok as we don't share this wrapper with KFServing.