Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=54248
Need to reset the decoder when the N2C converter is recycled to ensure BOMs are correctly handled for those encodings that require them.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1430079 13f79535-47bb-0310-9956-ffa450edef68