fix for GRAILS-10613 "request.exception returns "Method name must not be null" when exception in thrown in UrlFilters"
Merge branch '2.2.x'

Conflicts:
	grails-plugin-url-mappings/src/main/groovy/org/codehaus/groovy/grails/web/mapping/filter/UrlMappingsFilter.java
	grails-web/src/main/groovy/org/codehaus/groovy/grails/web/servlet/ErrorHandlingServlet.java
	grails-web/src/main/groovy/org/codehaus/groovy/grails/web/util/WebUtils.java