adding 2.2.1 release notes
typo fix
Merge pull request #715 from pulp/mhrivnak-release-notes

adding 2.2.1 release notes
Merge pulp-2.2 => pulp-2.3, pre-build
Automatic commit of package [pulp] release [2.2.1-1].
Automatic commit of package [pulp-builtins] release [2.2.1-1].
Automatic commit of package [pulp-nodes] release [2.2.1-1].
Merge (-s ours) pulp-2.2 => pulp-2.3, post-build
Merge commit 'b1df66da13197e51d73de966bbe90e7cbce19e33'
Merge branch 'pulp-2.3', post 2.2 build.