getdeps: distinguish build vs install steps in run_cmake.py
getdeps: distinguish build vs install steps in run_cmake.py

Summary:
Update the generated `run_cmake.py` script to allow the caller to specify that
they just want to run a build without the install step.

Reviewed By: wez

Differential Revision: D16778007

fbshipit-source-id: 1859aca2b80fa7b099b4790682a6508e0185f2a0

facebook/wangle,facebook/wangle,facebook/wangle