Create a legacy branch for Jetpack 2.1.



git-svn-id: http://plugins.svn.wordpress.org/jetpack/branches/2.1@650794 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update the 2.1 legacy branch.



git-svn-id: http://plugins.svn.wordpress.org/jetpack/branches/2.1@663290 b8457f37-d9ea-0310-8a92-e5e31aec5664