HBASE-26418 Update downloads.xml for release 2.4.8
HBASE-26418 Update downloads.xml for release 2.4.8

Signed-off-by: Andrew Purtell <b91237ce35d325aea9eacb2c17af89139c6c9289@apache.org>

mahak/hbase,apurtell/hbase,mahak/hbase,ndimiduk/hbase,Apache9/hbase,apurtell/hbase,ndimiduk/hbase,ndimiduk/hbase,Apache9/hbase,ndimiduk/hbase,Apache9/hbase,mahak/hbase,mahak/hbase,apurtell/hbase,Apache9/hbase,mahak/hbase,Apache9/hbase,ndimiduk/hbase,ndimiduk/hbase,Apache9/hbase,mahak/hbase,ndimiduk/hbase,mahak/hbase,apurtell/hbase,ndimiduk/hbase,Apache9/hbase,apurtell/hbase,mahak/hbase,mahak/hbase,apurtell/hbase,Apache9/hbase,Apache9/hbase,apurtell/hbase,mahak/hbase,apurtell/hbase,ndimiduk/hbase,ndimiduk/hbase,Apache9/hbase,apurtell/hbase,apurtell/hbase