[CMake] Bump -- CMAKE_INSTALL_PREFIX weirdness.

[kent williams]

There seems to be something unique about our build system that is
causing this problem, and I am beginning to suspect what it is: It
calls cmake to do a command-line configure even if the build directory
is already configured.

This is kind of ridiculous to do, I know, but for one thing, the
configure target in the Makefile depends on the Makefile itself, with
the rationale that if you change the Makefile, then you're conceivably
changing the flags passed in to CMake, so you should call CMake again
to make sure.  For another, our gnu-make build system is 10+ years old
and has turned into a giant ball of tangled barbed wire.

I think I can fix the problem by deleting the CMakeCache.txt file
before the call to cmake.  But should I have to do this?