Update custom xref query (eunit_test calls)

eunit_test:function_wrapper/2 was renamed to eunit:mf_wrapper/2 in
R15B02. Ignore both calls like we do with escript:foldl/3.

rebar.config

@@ -10,6 +10,8 @@
 {xref_queries,
  [{"(XC - UC) || (XU - X - B
       - (\"escript\":\"foldl\"/\"3\")
+      - (\"eunit_test\":\"function_wrapper\"/\"2\")
+      - (\"eunit_test\":\"mf_wrapper\"/\"2\")
       - (\"abnfc\":\"file\"/\"2\")
       - (\"erlydtl\":\"compile\"/\"3\")
       - (\"lfe_comp\":\"file\"/\"2\")