Remove redundant files

The branch-3.0.0.xml is identical to branch-master.xml, hence
not needed. A new branch 3.0.0.xml will be created once the
differs from master.

Change-Id: Ibf7283197434b5e20012566985d84c401d74e1fb
Reviewed-on: http://review.couchbase.org/27369
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>