spec: rspec3ify bullet pending

Change-Id: If8fc87f778cc4883d4abadcdcf173a74da64e6cd
Reviewed-on: https://gerrit.instructure.com/42897
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>