Pcbnew: try to fix an issue about frame title.

for Pcbnew, this issue (see bug 8404) is only seen on OSX.
So I am blindly trying to add to Pcbnew a fix made for Eeschema.

pcbnew/files.cpp

@@ -1140,6 +1140,8 @@ bool PCB_EDIT_FRAME::doAutoSave()
 {
     wxFileName tmpFileName;
 
+    wxString title = GetTitle();    // Save frame title, that can be modified by the save process
+
     if( GetBoard()->GetFileName().IsEmpty() )
     {
         tmpFileName = wxFileName( PATHS::GetDefaultUserProjectsPath(), wxT( "noname" ),
@@ -1184,11 +1186,15 @@ bool PCB_EDIT_FRAME::doAutoSave()
             GetSettingsManager()->TriggerBackupIfNeeded( NULL_REPORTER::GetInstance() );
         }
 
+        SetTitle( title );      // Restore initial frame title
+
         return true;
     }
 
     GetBoard()->SetFileName( tmpFileName.GetFullPath() );
 
+    SetTitle( title );      // Restore initial frame title
+
     return false;
 }