The package names in the python-build files for anaconda2-4.2.0 and
anaconda2-4.3.0 both had 'Anaconda2-4.2.1-MacOSX-x86_64' erroneously
listed as the package name. Anaconda2-4.2.1 is not a version of Anaconda
in existence. The URL arguments were correct, just not the package name
arguments.