re-enable detection of MVC for tests

MVC3 test was failing if MVC3 was not installed. Seems this was disabled
previously to allow some other tests that use MVC2 to run regardless, but
it'd be better to refactor those tests (or comment out their detection
only)

git-svn-id: https://svn.apache.org/repos/asf/incubator/npanday/trunk@1616412 13f79535-47bb-0310-9956-ffa450edef68