HBASE-7889 Fix javadoc warnings in snapshot classes, part 2 (Ted Yu)


git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/hbase-7290v2@1448485 13f79535-47bb-0310-9956-ffa450edef68
HBASE-7889 ADDENDUM (convert @code to simplified @links)


git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/hbase-7290v2@1448496 13f79535-47bb-0310-9956-ffa450edef68