Don't free() the handle after dlclose
Don't free() the handle after dlclose

Of the possible code paths, there was only one that freed the handle
after calling dlclose.  This change removes that free() statement,
fixing an issue that was recently brought to light by
JuliaLang/julia#10808.

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