Ignore sizzle.js in ESLint
Ignore sizzle.js in ESLint

This has > 6000 errors, and it's not our source. This makes
`eslint test/common/` work as expected.

cockpit-project/cockpit,cockpit-project/cockpit,mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit,mvollmer/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,mvollmer/cockpit,martinpitt/cockpit,martinpitt/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit