Fixes all errors that came with Elixir version changes

[mnrk]

Works for me, I would be great to merge it in!

[whitfin]

I'm not sure I understand what this is doing... Which OTP version changed that signature?

[scarfacedeb]

@whitfin There was a regression in :dets. See: https://elixirforum.com/t/erlang-dets-open-file-error-i-cant-understand-and-fix/14748/2

[whitfin]

Well, that's a pain.

I'm not going to merge this though; raising the minimum to v1.7 is "too much". I'm not entirely sure how to work around this because I don't really know how to detect OTP versions effectively... kinda sucks.

[krainboltgreene]

This is probably reasonable to do now.