copy the 0.5.0 tag to thrift-0.5.0 tag for consistency. leaving the old one in place so it doesn't confuse anyone.

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/tags/thrift-0.5.0@1028117 13f79535-47bb-0310-9956-ffa450edef68