lua_vmprep.c: Additional check to see if the resource list was successfully...

lua_vmprep.c: Additional check to see if the resource list was successfully created, so we don't end up trying to fetch a non-existent resource list when we use the 'server' option for the LuaScope directive.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1420181 13f79535-47bb-0310-9956-ffa450edef68