Activate hadoop1 profile by default for maven builds
Activate hadoop1 if property hadoop is missing. hadoop2 can be activated now
by using -Dhadoop -Phadoop2.
Activate hadoop2 profile in pom.xml with -Dhadoop=2
Rename environment variable for hadoop profiles to hadoopVersion
Merge pull request #355 from shivaram/default-hadoop-pom

Activate hadoop1 profile by default for maven builds