tdf#102688: let's purge it here just in case...

In theory it would still leak without this if the map mode is set
multiple times.

Change-Id: Ie862f4d59e45b92ff75dffb787ef256337f47f84
diff --git a/editeng/source/editeng/impedit2.cxx b/editeng/source/editeng/impedit2.cxx
index 5bbb325..7c6e51c 100644
--- a/editeng/source/editeng/impedit2.cxx
+++ b/editeng/source/editeng/impedit2.cxx
@@ -208,6 +208,7 @@ void ImpEditEngine::SetRefMapMode( const MapMode& rMapMode )
    if ( GetRefDevice()->GetMapMode() == rMapMode )
        return;

    mpOwnDev.disposeAndClear();
    mpOwnDev = VclPtr<VirtualDevice>::Create();
    pRefDev = mpOwnDev;
    pRefDev->SetMapMode( MapUnit::MapTwip );