qt: use deleteLater to remove send entries

Use deleteLater() instead of delete, as it is not allowed
to delete widgets directly in an event handler.
Should solve the MacOSX random crashes on send with coincontrol.

src/qt/sendcoinsdialog.cpp

@@ -260,7 +260,7 @@ void SendCoinsDialog::clear()
     // Remove entries until only one left
     while(ui->entries->count())
     {
-        delete ui->entries->takeAt(0)->widget();
+        ui->entries->takeAt(0)->widget()->deleteLater();
     }
     addEntry();
 
@@ -306,7 +306,7 @@ void SendCoinsDialog::updateTabsAndLabels()
 
 void SendCoinsDialog::removeEntry(SendCoinsEntry* entry)
 {
-    delete entry;
+    entry->deleteLater();
 
     // If the last entry was removed add an empty one
     if (!ui->entries->count())