D-Bus testing: catch server startup failure

When starting the server fails, an exception gets thrown when
trying to determine its pid. This used to abort the whole
test script without recording much information. In particular
the server's output was not included.

Now the exception is caught, recorded as error and testing continues
with the next test.

This did not fix the root cause (a stuck process occupied the
D-Bus name) but at least it helped to identify the problem.

test/test-dbus.py

@@ -564,7 +564,13 @@ class DBusUtil(Timeout):
 
         # pserver.pid is not necessarily the pid of syncevo-dbus-server.
         # It might be the child of the pserver process.
-        self.pserverpid = self.serverPid()
+        try:
+            self.pserverpid = self.serverPid()
+            self.running = True
+        except:
+            result.errors.append((self,
+                                  "server startup failed: %s\nchildren: %s" % (traceback.format_exc(), self.getChildren())))
+            self.running = False
 
         numerrors = len(result.errors)
         numfailures = len(result.failures)
@@ -587,8 +593,8 @@ class DBusUtil(Timeout):
         else:
             logging.printf('killing test disabled')
         try:
-            self.running = True
-            unittest.TestCase.run(self, result)
+            if self.running:
+                unittest.TestCase.run(self, result)
         except KeyboardInterrupt, ex:
             # somehow this happens when timedout() above raises the exception
             # while inside glib main loop