1045214 - Enable synchronization over SSL.

I had spent some time converting the config validation to use Exceptions, but then I realized that the InvalidConfig Exception has two problems:

1) It has a less than great API, and

2) It's not a Pulp coded Exception, so it wouldn't work.

Therefore, I backed out those changed and kept return True/False, msg ☹.

https://bugzilla.redhat.com/show_bug.cgi?id=1045214