s3-auth use create_local_token() to transform server_info -> session_info

s3-auth use create_local_token() to transform server_info -> session_info

Before a auth_serversupplied_info struct can be used for
authorization, the local groups and privileges must be calculated.
create_local_token() now copies the server_info, and then sets the
calulated token and unix groups.

Soon, it will also transform the result into an expanded struct
auth_session_info.  Until then, the variable name (server_info vs
session_info provides a clue to the developer about what information
has been entered in the structure).

By moving the calls to create_local_token within the codebase, we
remove duplication, and ensure that the session key (where modified)
is consistently copied into the new structure.

Andrew Bartlett