Fix two more errors in jspxml.dtd, found by validating the file in Eclipse IDE.
1. Complained for missing '(' in definition of jsp:text.
2. Element jsp:fallback (mentioned in jsp:plugin) was not defined.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1561732 13f79535-47bb-0310-9956-ffa450edef68