shaded AWS SDK in Hadoop JARs slowing ambari view loading

HADOOP-14040 moved Hadoop to using a fully shaded aws SDK JAR. While this addresses classpath grief downstream (jackson &c), apparently it hurts ambari view startup.

Why? There's now a very large aws JAR in web-inf/classes which Jetty scans looking for @servlet tags of some form or other, which takes a few seconds.

I'm willing to help fix this with whatever settings we can do to tell Jetty to stop this, as we aren't going to move back onto the older AWS SDKs: they're too much trouble.