Disable marvel as it may fail the tests, because it creates indices.

dev-tools/build_release.py

@@ -62,7 +62,6 @@ Once it's done it will print all the remaining steps.
 env = os.environ
 
 PLUGINS = [('license', 'elasticsearch/license/latest'),
-           ('marvel', 'elasticsearch/marvel/latest'),
            ('bigdesk', 'lukas-vlcek/bigdesk'),
            ('paramedic', 'karmi/elasticsearch-paramedic'),
            ('segmentspy', 'polyfractal/elasticsearch-segmentspy'),