Run each spec only once

When 'spec_helper' requires 'rspec/autorun' specs run more than once.

Calling `disable_autorun!` ensures each spec only runs once.

Change-Id: I06ba739ce0ac3c311e81b485c52b7600a1908ccb
Reviewed-on: https://gerrit.causes.com/27662
Reviewed-by: Shane da Silva <shane@causes.com>
Reviewed-by: Greg Hurrell <greg@causes.com>
Reviewed-by: John Skopis <john.skopis@causes.com>
Tested-by: John Skopis <john.skopis@causes.com>