CLOUDSTACK-6360: pick setJavaHome from 4.3 and master for 4.4 branch

A JAVA_HOME finder method was implemented by Rajani and got into master and 4.3
but not 4.4: https://reviews.apache.org/r/22721/

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>