Process exceptions when talking to Dogtag

The problem is the ca_status() uses an HTTP GET operation to check Dogtag's
status. Under some circumstances Dogtag may take a long time to respond, so the
HTTP GET may time out much earlier than 2 minutes. And since the above code
doesn't catch the exception, the whole loop fails immediately, so it doesn't
wait for a full 2 minutes as expected.

https://fedorahosted.org/freeipa/ticket/3492

ipapython/platform/fedora16/service.py

@@ -136,7 +136,10 @@ class Fedora16CAService(Fedora16Service):
         timeout = api.env.startup_timeout
         op_timeout = time.time() + timeout
         while time.time() < op_timeout:
-            status = dogtag.ca_status()
+            try:
+                status = dogtag.ca_status()
+            except Exception:
+                status = 'check interrupted'
             root_logger.debug('The CA status is: %s' % status)
             if status == 'running':
                 break