vchoi_fork

[svn-r11867] Purpose:
Makefile fix

Description:
perform/h5perf is (currently) a test for parallel performance, but was
being built when parallel was disabled.  Fixed this.
perform/perf had the same problem.

Solution:
Actually, perf and h5perf were being "built but not executed"
using two different mechansims.  They now use the same mechanism,
being built and executed in parallel only.

Platforms tested:
mir, heping, sleipnir