fixing a problem with fetching http hosted public keys

stupid syntax error (exception was actually caught) caused by me flip flopping languages… this (java) vs self (python), duh.

adding test to validate that fetch works and stores the public key without error.

Signed-off-by: Jim Klo <jim.klo@sri.com>
Merge pull request #258 from jimklo/http-public-key-fix

fixing a problem with fetching http hosted public keys