CMake warning without Python enabled

[burlen]

The following warning occurs when compiling TECA on NERSC cori. HAMR_ENABLE_PYTHON is in its default state OFF.

CMake Warning at HAMR/CMakeLists.txt:192 (find_package):
  By not providing "FindPython3.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "Python3", but
  CMake did not find one.

  Could not find a package configuration file provided by "Python3" with any
  of the following names:

    Python3Config.cmake
    python3-config.cmake

  Add the installation prefix of "Python3" to CMAKE_PREFIX_PATH or set
  "Python3_DIR" to a directory containing one of the above files.  If
  "Python3" provides a separate development package or SDK, be sure it has
  been installed.