disable asynchronous output for the ECL output test

this leads to crashes deeply inside libecl. My cursory hypotheses are
that this test makes the assumption that the output is written
synchronously (it tries to read back the results from disk
immediately) and/or that libecl is not threadsafe.

tests/test_ecl_output.cc

@@ -79,6 +79,7 @@ namespace Ewoms {
 namespace Properties {
 NEW_TYPE_TAG(TestEclOutputTypeTag, INHERITS_FROM(BlackOilModel, EclBaseProblem));
 SET_BOOL_PROP(TestEclOutputTypeTag, EnableGravity, false);
+SET_BOOL_PROP(TestEclOutputTypeTag, EnableAsyncEclOutput, false);
 }}
 
 static const int day = 24 * 60 * 60;