Mark 7.0.48 as not released based on the vote results.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1549904 13f79535-47bb-0310-9956-ffa450edef68
Update changelog

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1549911 13f79535-47bb-0310-9956-ffa450edef68