Remove unused import

Leftover, because Plotter is not used at all in this file.

Change-Id: Ib0682ae7225c1ddb532ff815f4cb6055b9ce4454
Signed-off-by: Martin Pavlasek <mpavlase@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/35411
Reviewed-by: Adam Litke <alitke@redhat.com>
Tested-by: Adam Litke <alitke@redhat.com>