Implement Java-APIs for flow filter.

Note that flow filter feature is not yet fully-implemented.
This patch enables to configure flow filters, but they will not work.

Change-Id: I54fa3bcbcacdd724ead08d22168f521cdd988da5
Signed-off-by: Shigeru Yasuda <s-yasuda@da.jp.nec.com>
Merge "Implement Java-APIs for flow filter."