Fixes #26 - use jdk_home instead of java_home for Linux
Fixes #26 - use jdk_home instead of java_home for Linux

Now that jdk_home is defined in Linux and differs from java_home, use that instead. Fixes oracle jdk problem.
CellProfiler/python-javabridge,CellProfiler/python-javabridge,CellProfiler/python-javabridge,CellProfiler/python-javabridge