Revert "Revert "spec: selenium 2.40 firefox 2.70 upgrades""

This reverts commit 4498b890bdf50b6702b8fc54eadd0c7573638298.

Change-Id: I73865e62e6953f78fa583427a99855719e300880
Reviewed-on: https://gerrit.instructure.com/32578
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Shawn Meredith <shawn@instructure.com>
Product-Review: Shawn Meredith <shawn@instructure.com>
QA-Review: Shawn Meredith <shawn@instructure.com>
Tested-by: Shawn Meredith <shawn@instructure.com>