Fix Joyent's `get_conn()` function.
`avail_locations()` was not namespaced for libcloud AWS.
Fix `--list-{locations,images,sizes}` to respect the provider alias.
Blacklist some cloud driver functions.

Because on the cloud drivers we do `from saltcloud.libcloudfuncs import *` which simplifies code readability, it adds some unsupported functions into the driver's module scope. The black listed functions will be removed from the loader.