b2_authorize_account and b2_list_bucket request fix.

B2 has changed how they authenticate and handle b2_list_bucket requests on July 26th, 2018 that broke b2_list_bucket requests.

https://www.backblaze.com/b2/docs/b2_list_buckets.html

From my testing using curl:

You need to use the keyId generated when you make the authorization key instead of accountId when calling b2_authorize_account but have to use accoutId when you call b2_list_buckets.

Otherwise you get a 401, "unauthorized" error for b2_authenticate_account and 400, "accountId invalid" when you call b2_list_buckets.

Note: the reply from b2_authorize_account contains the accountId and could be stored or returned for the Bucket function.