Simplify code around re-raising an error.
Simplify code around re-raising an error.

"By using raise with no arguments, you will re-raise the last exception."
- https://wiki.python.org/moin/HandlingExceptions

re: https://github.com/SUSE/azurectl/pull/52#discussion_r40293596

SUSE/azurectl,SUSE/azurectl,SUSE/azurectl