miniconda: `CONDA_PATH` -> `INSTALL_CONDA_PATH`.
miniconda: `CONDA_PATH` -> `INSTALL_CONDA_PATH`.

Appears that `CONDA_PATH` is now being used by `conda` and is being
unset in some cases. This changes the environment variable we use to
`INSTALL_CONDA_PATH` so that we don't conflict with `conda`.

jakirkham/docker_centos_drmaa_conda,nanshe-org/docker_centos_drmaa_conda,DudLab/docker_centos_drmaa_conda