Revising backend bool spec test that nil /= false
Revising backend bool spec test that nil /= false

If the backend lookup() was requested to return true then it would,
however if it was requested to return `false` or `nil` specifically (both of
which equate to "falsity" in ruby) then it would only respond with
`nil`. This revised spec test would fail previous to this bugfix.

MikaelSmith/hiera,joshcooper/hiera,hlindberg/hiera,johnduarte/hiera,justinstoller/hiera,ferventcoder/hiera,ripienaar/hiera,Iristyle/hiera,ferventcoder/hiera,hlindberg/hiera,johnduarte/hiera,MikaelSmith/hiera,justinstoller/hiera,Iristyle/hiera,Iristyle/hiera,MikaelSmith/hiera,justinstoller/hiera,hlindberg/hiera,ripienaar/hiera,ferventcoder/hiera,haus/hiera,johnduarte/hiera