Update INSTALL.md

[odellus]

Changed OCC commit point to to 7.5.3 tag because following README.md in it's current state yields the following error.

CMake Error at CMakeLists.txt:151 (find_package):
  Could not find a configuration file for package "OpenCASCADE" that is
  compatible with requested version "7.5.3".

  The following configuration files were considered but not accepted:

    /usr/local/lib/cmake/opencascade/OpenCASCADEConfig.cmake, version: 7.5.2
    /home/thomas/Downloads/occt-0dc2c37/cmake-build/OpenCASCADEConfig.cmake, version: 7.5.2