python3Packages.pywemo: disable failing test

[mweinelt]

Motivation for this change

With libxml2 2.9.12 this test started failing, it was reported upstream
at pywemo/pywemo#268.

Needs to be ported to 21.05.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• 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 nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Added a release notes entry if the change is major or breaking
• Fits CONTRIBUTING.md.

[r-rmcgibbo]

Result of nixpkgs-review pr 124385 at a0160c0 run on aarch64-linux 1

1 package failed to build:

• home-assistant

2 packages built successfully:

• python38Packages.pywemo
• python39Packages.pywemo

Note that build failures may predate this PR, and could be nondeterministic or hardware dependent.
Please exercise your independent judgement. Does something look off? Please file an issue or reach out on IRC.

[fabaff]

Looks good to me.

[jonringer]

This is unnecessary with staging-next patch.

[mweinelt]

Let's revert this in staging-next then.

[jonringer]

probably a good solution, so that others don't try to fix the build either