* testing: replace most goe/verify.Values with require.Equal
One difference between these two comparisons is that go/verify considers
nil slices/maps to be equal to empty slices/maps, where as testify/require
does not, and does not appear to provide any way to enable that behaviour.
Because of this difference some expected values were changed from empty
slices to nil slices, and some calls to verify.Values were left.
* Remove github.com/pascaldekloe/goe/verify
Reduce the number of assertion packages we use from 2 to 1
This PR both prevents a blank CA config from being written out to
a snapshot and allows Consul to gracefully recover from a snapshot
with an invalid CA config.
Fixes#4954.
