All proxy APIs are now deprecated which includes
sec grp APIs also.
But list sec grps by server API-
(/servers/{server_id}/os-security-groups) is not
deprecated so this should be separated from deprecated
sec grp APIs in api-ref.
Partially implements blueprint deprecate-api-proxies
Change-Id: I9f9e2cf5f8e390cecd9e1794a0af1a3fcc24f149
