Use fifo instead of Qthreads when testing on mac os version < 10.

Qthreads does not support mac os versions less than 10, so this updates smoke
and correctness tests to use fifo on the old mac used for chapel testing.
Merge pull request #223 from thomasvandoren/test-with-fifo-on-old-mac

Use fifo instead of Qthreads when testing on mac os version < 10.

Qthreads does not support mac os versions less than 10, so this updates smoke
and correctness tests to use fifo on the old mac used for chapel testing.

reviewed by @ronawho