Upgrade RSpec from 2.13.0 -> 2.14.1

In the process, silence a deprecation warning by renaming a use of
`stub!` to `stub`.

Change-Id: Ice7ed367967976a2f572c56f7a58a64e5102f023
Reviewed-on: https://gerrit.causes.com/33013
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>