BUG: Use fixed seed for Vnl FFT tests for repeatibility.

The previous seed was based on the system.  A partial set of dashboard
submissions saw failed tests on 2014-07-20. Use a fixed random number
seed so test results are repeatable.

Change-Id: I6cd3c54d3a827c534ee2498f1979848738b02727
Merge topic 'VnlFFTTestSeed'

cf9bbb70 BUG: Use fixed seed for Vnl FFT tests for repeatibility.