Fixed problem in eeschema when leaving sub sheet in a hierarchy.

(two scrolling parameters were different when calling SetScroolBars in drawframe.cpp and hierarch.cpp 

eeschema/hierarch.cpp

@@ -308,8 +308,9 @@ static bool UpdateScreenFromSheet( WinEDA_SchematicFrame* frame )
     // Reset display settings of the new screen
     // Assumes m_CurrentSheet has already been updated.
     frame->ClearMsgPanel();
-    frame->DrawPanel->SetScrollbars( NewScreen->m_ZoomScalar,
-                                     NewScreen->m_ZoomScalar,
+    int pixelsPerUnitX = 1;
+    int pixelsPerUnitY = 1;
+    frame->DrawPanel->SetScrollbars( pixelsPerUnitX, pixelsPerUnitY,
                                      NewScreen->m_ScrollbarNumber.x,
                                      NewScreen->m_ScrollbarNumber.y,
                                      NewScreen->m_ScrollbarPos.x,