Remove deprecated mappedBy.
Remove deprecated mappedBy.

Committed: https://code.google.com/p/dart/source/detail?r=18575
Reverted: http://code.google.com/p/dart/source/detail?r=18576

Review URL: https://codereview.chromium.org//12212213

git-svn-id: a0fc6a377c96b9059f80895148836233a16d98be@18579 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/http,donny-dont/http,dart-lang/http,dart-lang/http,kasperpeulen/http,dart-lang/http,dart-lang/http,dart-lang/http,dart-lang/http,dart-lang/http