Remove clean-plugin from parent pom

This plug-in is no longer required and some .ser files were accidentally
deleted, therefor removing it completely.

Change-Id: I5183d71020d27fb1f876c6cd5d2155ed77409938
Signed-off-by: Denis Knoepfle <denis.knoepfle@sap.com>
Simplify and prepare for result fetching via job ids

Change-Id: I2dbbfb086d544ac13e6408d2c4fb2ed56f78f883
Signed-off-by: Denis Knoepfle <denis.knoepfle@sap.com>