Update steps-deploy-replica-set-with-auth.yaml

Step 12 duplicates Step 2 where you add user "siteUserAdmin" with role "userAdminAnyDatabase".

Signed-off-by: kay <kay.kim@10gen.com>
trivial: step using keyfile now refers to the created keyfile in previous step
DOCS-3952 - Typo fix s/including as HIPAA/including HIPAA/
Fix release notes link to 2.6.4 SERVER ticket

Signed-off-by: Sam Kleinman <samk@10gen.com>