Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=55905
Merged revision 1552071 from tomcat/trunk:
Prevent NPE when the specified tld resource does not exists.


git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1552074 13f79535-47bb-0310-9956-ffa450edef68