mark specs as pending if saml is not enabled

Depending on which specs were running, AccountAuthorizationConfig might
not have even been loaded before this change, causing Onelogin to be a
missing constant even if SAML is available.

refs CNVS-10467 (fixes a travis.ci build error)

Change-Id: Ifcc93db91f0cb25deab39c1fe3e60dc3e8b63451
Reviewed-on: https://gerrit.instructure.com/28940
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: Bryan Madsen <bryan@instructure.com>
QA-Review: Bryan Madsen <bryan@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>