Pass the relaxed option when downloading rebar
Pass the relaxed option when downloading rebar

Closes #2152

kelvinst/elixir,kelvinst/elixir,elixir-lang/elixir,antipax/elixir,kimshrier/elixir,antipax/elixir,michalmuskala/elixir,pedrosnk/elixir,pedrosnk/elixir,kimshrier/elixir,lexmag/elixir,beedub/elixir,lexmag/elixir,beedub/elixir,ggcampinho/elixir,ggcampinho/elixir,gfvcastro/elixir,joshprice/elixir,gfvcastro/elixir