install.py ignores --with-cmake for scikit-build

[syamajala]

install.py is not passing cmake_exe to scikit-build, which results in that part of the build process using the wrong cmake.

(/sdf/home/s/seshu/cunumeric-cpu) [seshu@sdfiana002 legate.core]$ ./install.py --legion-src-dir /sdf/home/s/seshu/cunumeric-cpu/legion --openmp --no-cuda --network ucx -j8 --verbose --clean --with-cmake /sdf/home/s/seshu/cunumeric-cpu/bin/cmake

Verbose build is on                                                                                                    
networks: ['ucx']                                                                                                      
cuda: False                                                                                                            arch: all-major                                                                                                        
openmp: True                                                                                                           
march: haswell                                                                                                         hdf: False                                                                                                             
llvm: False                                                                                                            
spy: False                                                                                                             
build_docs: False                                                                                                      
conduit: None                                                                                                          
gasnet_system: None                                                                                                    
nccl_dir: None                                                                                                         
cmake_exe: /sdf/home/s/seshu/cunumeric-cpu/bin/cmake  
...

I can see it still calls /usr/bin/cmake3:

 Not searching for unused variables given on the command line.
  CMake Error at CMakeLists.txt:17 (cmake_minimum_required):
    CMake 3.22.1 or higher is required.  You are running version 3.20.2
                           
                                                                                                                      
  -- Configuring incomplete, errors occurred!
  Traceback (most recent call last):
    File "/sdf/home/s/seshu/cunumeric-cpu/lib/python3.9/site-packages/skbuild/setuptools_wrap.py", line 666, in setup        env = cmkr.configure(
    File "/sdf/home/s/seshu/cunumeric-cpu/lib/python3.9/site-packages/skbuild/cmaker.py", line 357, in configure
      raise SKBuildError(msg)                                                                                              
  An error occurred while configuring with CMake.
    Command:
                                                                                                        
/usr/bin/cmake3 /sdf/home/s/seshu/cunumeric-cpu/legate.core...