Non existing plugin dependency org.eclipse.vex.docbook.source removed.

The docbook plugin does not contein source code any more. Then
dependency caused a warning on hudson and an error for local builds.

Change-Id: I112e02f4e4253fa15cf7bf3be40286ca86bc6f75
Signed-off-by: Carsten Hiesserich <carsten.hie@gmail.com>
1 file changed