Do not install default-jre-headless on Ubuntu

The java cookbook's default recipe already installs the correct version
of Java as configured in the node attributes.
Installing default-jre-headless always installs JDK 6.
See https://github.com/socrata-cookbooks/java/pull/80 for more details.
Determine LD_LIBRARY_PATH for libjvm.so automatically
Fix code style
Merge pull request #25 from mbautin/do_not_install_default_jre_headless

Do not install default-jre-headless on Ubuntu