Fix check_for_setup_error for sheepdog driver

Current implementation of check_for_setup_error() of sheepdog driver
cannot work correctly with the latest version of sheepdog cluster.
This patch fixes it and adds tests for both old and new version.

Fixes: bug #1195098
Change-Id: Ia710789e4bedd7c83cd47eff6b2fc532af39d94a
Merge "Fix check_for_setup_error for sheepdog driver"