Define property that specifies packages to be excluded from javadoc.
Define property that specifies packages to be excluded from javadoc.

"javadoc.exclude" property value is passed to maven-javadoc-plugin as
"excludePackageNames" value on both "site" and "javadoc" goals.

Change-Id: If98837799cf0179075e08e83969979b54c76589c
Signed-off-by: Shigeru Yasuda <4286dc62f6b184926d282535950a80f031d65860@da.jp.nec.com>

opendaylight/vtn,opendaylight/vtn,opendaylight/vtn,opendaylight/vtn,opendaylight/vtn,opendaylight/vtn,opendaylight/vtn