RFE: make -m/--with-cmake override default cmake

[rouson]

Avg response time

Observed Behavior

-m/--with-cmake do not override the use of a cmake that is in the default installation location (prerequisites/installations/cmake/3.4.0)

Expected Behavior

Because the corresponding --with- flags for the compilers and for MPI all override the defaults, it would be more consistent to make the same true for --with-cmake.

Steps to Reproduce

On grover platform at U. Oregon:

./install.sh \
-M /home/users/rouson/opencoarrays/prerequisites/installations/mpich/3.2/ \
--install-prefix /home/users/rouson/opencoarrays/prerequisites/installations/opencoarrays/1.9.0/gnu/7.1.0  \
-j 8 \
--with-cmake /home/users/rouson/opencoarrays/prerequisites/installations/cmake/3.8.0/bin/cmake

Request for Enhancement (RFE)

I'll submit a pull request shortly that implements the expected behavior.