MB-9475:  2.5 READMEs in correct location

Change-Id: I9b365657e6b3b455b7b80c33bc839901e6717684
Reviewed-on: http://review.couchbase.org/32692
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>