Fix error thrown by test_success if curl/wget/fetch command not found
Fix error thrown by test_success if curl/wget/fetch command not found

JuliaPackageMirrors/BinDeps.jl,tlycken/BinDeps.jl,rened/BinDeps.jl,andrewcooke/BinDeps.jl,tkelman/BinDeps.jl,chezou/BinDeps.jl