spec: fix selenium/collaborations_spec for rails 3

Change-Id: Ia1ddfc2e6979b3d5ad377664f0693f9eda4eafd4
Reviewed-on: https://gerrit.instructure.com/30392
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>
QA-Review: James Williams  <jamesw@instructure.com>