Debugger/Python dumper: Fix checkRef() for Qt 5.

See http://codereview.qt-project.org/4533
(1173d0420e341dc6d38c89e5bc4295a57da7ea74 in qtbase)

Change-Id: I13d249c592b2607ee96c2feacbaefb73dd926867
Reviewed-on: http://codereview.qt-project.org/6324
Sanity-Review: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: hjk <qthjk@ovi.com>

share/qtcreator/dumper/dumper.py

@@ -425,7 +425,11 @@ def check(exp):
         raise RuntimeError("Check failed")
 
 def checkRef(ref):
-    count = ref["_q_value"]
+    count = 0
+    if qtMajorVersion() >= 5:
+        count = ref["atomic"]["_q_value"]
+    else:
+        count = ref["_q_value"]
     check(count > 0)
     check(count < 1000000) # assume there aren't a million references to any object