lucene-jobs: convert java opts to shell variables

We pass some non standard options (-X*) to the lucene.jobs.sh java
calls.  This move them to shell variables at the top of the document,
will later let us override them by sourcing a configuration file.

Change-Id: I6398ab0c8af9486d39b86dd6243152f9af61e04e
Merge "lucene-jobs: convert java opts to shell variables" into production