Report unexpected exit codes from libcloud_wrapper
Report unexpected exit codes from libcloud_wrapper

Previously, if libcloud_wrapper returned with an exit code different from 0, 1,
2 and 3, elibcloud would throw a case_clause error. This could happen e.g. when
the libcloud process was killed by the operating system with "kill -9", which
produces exit code 137.

Now elibcloud accepts all exit codes and reports them back to the caller.

esl/elibcloud,hcs42/elibcloud