cmake: Localize CMake POD binary directory computation
cmake: Localize CMake POD binary directory computation

Move the `${proj}_BINARY_DIR` value computed for CMake PODs into the
corresponding code path.  It is not needed for non-CMake PODs and has an
incorrect value for them otherwise.

sheim/drake,sheim/drake,billhoffman/drake,billhoffman/drake,sheim/drake,billhoffman/drake,sheim/drake,sheim/drake,billhoffman/drake,sheim/drake,billhoffman/drake,billhoffman/drake,sheim/drake,billhoffman/drake,sheim/drake,billhoffman/drake