SPARK-1297 Upgrade HBase dependency to 0.98

Two profiles are added to examples/pom.xml :
hbase-hadoop1 (default)
hbase-hadoop2

I verified that compilation passes with either profile active.
Is this necessary here? Hadoop is also sensitive to this version and so this is controlled by the Hadoop profile. I am not sure it gains you anything to specify it separately here. If you specify an incompatible combination it's still going to not work no matter what. That is, it goes without saying that one would set this already by choosing `-Phadoop-2.3` or something.