vdirsyncer: disable flaky test

[wirew0rm]

Motivation for this change

Since #103073 the hydra build of vdirsyncer was broken.

Disables sync_test:test_create_collection, a flaky test which exceeds its
deadline and breaks the build on hydra, e.g this hydra build log

Upstream vdirsyncer issue: pimutils/vdirsyncer#837

Since things seem to work for most people, my guess is that it works on beefier machines than my laptop or the hydra builder. I don't know if there is some way to increase the test timeout easily or if this is actually some performance regression.

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 rev fixVdirsyncerTest"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[mweinelt]

= 1 failed, 369 passed, 115 skipped, 1 deselected, 2601 warnings in 83.70s (0:01:23) =

This does not seem to be a timeout issue and I can't reproduce the error locally.

[mweinelt]

LGTM wrt the upstream issue and the hydra failure vs. me being unable to repro.

[mweinelt]

Result of nixpkgs-review pr 105277 run on x86_64-linux 1

3 packages built:

• khal
• python37Packages.vdirsyncer
• vdirsyncer (python38Packages.vdirsyncer ,vdirsyncerStable)