[PAXWEB-474] - set context attributes before context start +
filter integration test
Conflicts:
	itest/src/test/java/org/ops4j/pax/web/itest/WarIntegrationTest.java
	pax-web-jetty/src/main/java/org/ops4j/pax/web/service/jetty/internal/HttpServiceContext.java

Conflicts:
	pax-web-jetty/src/main/java/org/ops4j/pax/web/service/jetty/internal/HttpServiceContext.java