Fix uninitialized variables in advanced digitizing dock which meant

that sometimes advanced digitising tools would be activated
unexpectedly.

(Coverity... I'm disappointed. Stop slacking off! I've fixed 1000s
of these warnings you flagged yet you missed the ones which trigerred
actual real bugs)

src/gui/qgsadvanceddigitizingdockwidget.cpp

@@ -89,12 +89,13 @@ bool QgsAdvancedDigitizingDockWidget::lineCircleIntersection( const QgsPoint& ce
 QgsAdvancedDigitizingDockWidget::QgsAdvancedDigitizingDockWidget( QgsMapCanvas* canvas, QWidget *parent )
     : QDockWidget( parent )
     , mMapCanvas( canvas )
+    , mCurrentMapToolSupportsCad( false )
     , mCadEnabled( false )
     , mConstructionMode( false )
     , mSnappingMode(( QgsMapMouseEvent::SnappingMode ) QSettings().value( "/Cad/SnappingMode", QgsMapMouseEvent::SnapProjectConfig ).toInt() )
     , mCommonAngleConstraint( QSettings().value( "/Cad/CommonAngle", 90 ).toInt() )
-    , mCadPointList( QList<QgsPoint>() )
-    , mSnappedSegment( QList<QgsPoint>() )
+    , mSnappedToVertex( false )
+    , mSessionActive( false )
     , mErrorMessage( 0 )
 {
   setupUi( this );