pythonPackages.sqlalchemy: 1.2.7 -> 1.2.8

[dtzWill]

http://docs.sqlalchemy.org/en/latest/changelog/changelog_12.html#change-1.2.8

Also fixes test failures w/musl, although I haven't investigated this
further than seeing if they persisted with most recent version O:).

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

[dtzWill]

Oh I didn't expect so many things to depend on this. Will send to staging instead.

[dtzWill]

(sorry for auto-review-requests issued while rebasing + telling github about it)

[dtzWill]

Waiting at least a bit for @FRidh's approval :).

[nh2]

@dtzWill What does the error look like that this fixes? Could you post them?

I found some other python tests in some other builds (dependencies of ghc) failing with musl that are related to TCP buffers (namely pyca/pyopenssl#768), and woud like to know if this is somewhat similar.

[FRidh]

I've just pushed this update to staging.