TermTagger Connector must give an error when on the configured TCP port no termtagger is listening

Problem: On our server port 9001 is used for atlassian stuff, but the default installation uses port 9001 for the termtagger. A test import was stucking in an termtagging endless loop without giving an error since a valid HTTP answer was coming from 9001, although it was no termtagging answer.

Solution: Our Termtagging connector must also through an error when the received HTTP answer is nothing from the termtagger.