Fix handling of empty user home flag in System.user_home/0 (#9991)
Fix handling of empty user home flag in System.user_home/0 (#9991)

According to erlang documentation, :init.get_argument/1 returns :error when no value is associated with the flag: http://erlang.org/doc/man/init.html
kimshrier/elixir,kelvinst/elixir,kimshrier/elixir,michalmuskala/elixir,pedrosnk/elixir,ggcampinho/elixir,ggcampinho/elixir,kelvinst/elixir,elixir-lang/elixir,pedrosnk/elixir,joshprice/elixir