[mock goal] do not log exception as a MojoFailureException is thrown

[redfish4ktc]

This duplicates the error log, so remove it as we did for the test goal (see #2)

        try {
            runner.run();
        } catch (Exception e) {
            getLog().error(e.toString());
            throw new MojoFailureException(this, "SoapUI MockService(s) failed", e.getMessage());
        }

[redfish4ktc]

Also add the exception cause to the MojoFailureException.
Implementation done in the mock-goal branch. Ready to be merged in master

[redfish4ktc]

Merged in master.
Fixed in 4.5.1.2