The install() function in the miniconda2 & 3 package.py files referenced
self.url, which is hard-coded to 4.3.11. That's not necessary the
version that the user requested, though. Changed the install() function
to reference self.stage.archive_file. Also added a version string for
4.5.11.
- remove the old LGPL license headers from all files in Spack
- add SPDX headers to all files
- core and most packages are (Apache-2.0 OR MIT)
- a very small number of remaining packages are LGPL-2.1-only
