Calendar example: sql module required

Change-Id: I75eb50a053f429135d1d49d1769b85a247c30311
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>

examples/quick/controls/controls.pro

 TEMPLATE = subdirs
 
 SUBDIRS += \
-    calendar \
     gallery \
     splitview \
     tableview \
@@ -11,3 +10,7 @@ SUBDIRS += \
 qtHaveModule(widgets) {
     SUBDIRS += texteditor
 }
+
+qtHaveModule(sql) {
+    SUBDIRS += calendar
+}