Move up Hadoop in pom.xml and add back protobufs

As Hadoop 1.0.4 doesn't use protobufs, we can't exclude protobufs from Spark always. This change tries to order the dependencies so that the shading plugin first picks up Hadoop's protobufs over Mesos.

Note that this should all go away once Mesos shades their jars https://issues.apache.org/jira/browse/MESOS-1203

This should hopefully fix #41