Handle fatal file system errors in SoSReport.final_work()

Out-of-space and read-only file system errors while creating the
compressed archive should be treated as fatal and cause the run
to end.

Partial fix for Issue #266.

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>
Handle IOError exceptions in SoSReport

Write operations raise IOError instead of OSError and do not
expose a filename attribute.

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>