"Release" switches now have a realistic expiry date.

Also removed live blog caching switch
Merge branch 'master' of github.com:guardian/frontend into switch-me-on

Conflicts:
	common/app/conf/switches.scala
Merge branch 'master' of github.com:guardian/frontend into switch-me-on

Conflicts:
	common/app/conf/switches.scala
Merge pull request #6124 from guardian/switch-me-on

"Release" switches now have a realistic expiry date.