test: Don't assume package name in path
test: Don't assume package name in path

On Julia 0.7 Travis it appears that the package gets cloned into
Documenter.jl, which makes that check invalid. We probably shouldn't
make any assumptions about the name of the package directory.

JuliaDocs/Documenter.jl,mortenpi/Documenter.jl,MichaelHatherly/Lapidary.jl