spec: don't leave a bad reference in @@shard1 around when creation fails

Change-Id: I0954e0e0cc983e0ea0d7843d2464e8e039794d66
Reviewed-on: https://gerrit.instructure.com/29631
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: James Williams  <jamesw@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>
increase guarantees of RSpecHelper

i.e. outside of the context that it's included into, Shard.default will
revert to a DefaultShard

Change-Id: Iee07b1f7dc07e1425644b2df3d073afc8baddb00
Reviewed-on: https://gerrit.instructure.com/29764
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jacob Fugal <jacob@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>
spec: make it not take so long

192.168.1.1 might be routable and drop the packets, so use a dummy name
that won't resolve instead

Change-Id: I4215f9de1f3fde68b3d803f6f2b79ca75a1a6535
Reviewed-on: https://gerrit.instructure.com/29765
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Ryan Florence <ryanf@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>