Super_admin_key role restriction and attrib fixes

* Do not role restrict super_admin_key in proxy config.  At one
point it was thought this may increase security by having the
super key only available on the management server, but this
is incompatible with some addon pipeline items like tempurl.
* Correct swauth_version attribute in proxy recipe which was
referenced incorrectly as swauth-version, leading to no swauth
installation action taking place
* Treat platform_options["swauth_packages"] properly as a
list which is how it is defined in attributes
* Further discoveries of swauth-source vs swauth_source
discrepancies corrected
* Cleanup guard check for swauth packages

Change-Id: Ia0579a4518f45f7a6d5602c22351361424134d85