NIFI-6944 fixed NiFiClientUtil.getUrl and modified NiFiClientUtilSpec…

[drewkerrigan]

… to test non-default WEB_HTTP_PORT

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fixes bug NIFI-6944.

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[drewkerrigan]

The build failure seems unrelated, although it is interesting that this line failed: https://github.com/apache/nifi/blob/master/nifi-nar-bundles/nifi-provenance-repository-bundle/nifi-persistent-provenance-repository/src/test/java/org/apache/nifi/provenance/index/lucene/TestLuceneEventIndex.java#L234 (assertEquals(5, nodes.size());, nodes.size() was actually 8, not 5). It may suggest another bug in either the test or the lucene event index code.