Eeschema: don't cleanup unseen schematics

Changes to the schematic shouldn't be made
where the user isn't looking.  Removing the
cleanup in ERC and netlisting prevents
unintended consequences

CHANGE: ERC and Netlist calls do not modify schematic

eeschema/dialogs/dialog_erc.cpp

@@ -478,15 +478,6 @@ void DIALOG_ERC::TestErc( wxArrayString* aMessagesList )
     // Erase all previous DRC markers.
     screens.DeleteAllMarkers( MARKER_BASE::MARKER_ERC );
 
-    for( SCH_SCREEN* screen = screens.GetFirst(); screen != NULL; screen = screens.GetNext() )
-    {
-        /* Ff wire list has changed, delete Undo Redo list to avoid pointers on deleted
-         * data problems.
-         */
-        if( screen->SchematicCleanUp() )
-            screen->ClearUndoRedoList();
-    }
-
     /* Test duplicate sheet names inside a given sheet, one cannot have sheets with
      * duplicate names (file names can be duplicated).
      */

eeschema/netlist.cpp

@@ -83,9 +83,6 @@ bool SCH_EDIT_FRAME::prepareForNetlist()
             return false;
     }
 
-    // Cleanup the entire hierarchy
-    schematic.SchematicCleanUp();
-
     return true;
 }
 
@@ -123,7 +120,6 @@ bool SCH_EDIT_FRAME::CreateNetlist( int aFormat, const wxString& aFullFileName,
         schematic.UpdateSymbolLinks();
         SCH_SHEET_LIST sheets( g_RootSheet );
         sheets.AnnotatePowerSymbols();
-        schematic.SchematicCleanUp();
     }
 
     std::unique_ptr<NETLIST_OBJECT_LIST> connectedItemsList( BuildNetListBase() );