Add -q option to fsck to check for zero-byte cache files quickly (#3726)

Update test logic in test 566 (#3713)

update changelog

bump to 2.11.4

bump version to 2.11.3

migrationtest: fix download of libs package

bump patch release version to 2.11.1

Merge pull request #3309 from cvmfs/fix-perf

Fix performance bug introduced by commit d67bfbd

update changelog: add tags for 2.11

fix-up make_repo test script