Add vanilla intel cc testing for knc.

It just tests that make succeeds. It makes no attempt to actually compile or run a program...
Unload all craype-intel-knc conflicts for vanilla test script.

suggested by @ronawho
Merge pull request #254 from thomasvandoren/test-vanilla-intel-knc

Add vanilla intel cc testing for knc.

It just tests that make succeeds. It makes no attempt to actually compile or run a program...

reviewed by @ronawho