Fix: Assembly startup logs harmless WARN about schemas

[mattrpav]

The schemas are included internally to tomcat's jasper support.

These are harmless for running in Jetty

WARN | The XML schema [XMLSchema.dtd] could not be found. This is very likely to break XML validation if XML validation is enabled.
 WARN | The XML schema [datatypes.dtd] could not be found. This is very likely to break XML validation if XML validation is enabled.
 WARN | The XML schema [xml.xsd] could not be found. This is very likely to break XML validation if XML validation is enabled.