Fix issue with miniconda attempting to install the incorrect version (#9589)

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.