test/example-gatt-server: Make test service primary

This allows to test from Android until included services support is
added.
diff --git a/test/example-gatt-server b/test/example-gatt-server
index 9944e02..24aaff9 100755
--- a/test/example-gatt-server
+++ b/test/example-gatt-server
@@ -438,7 +438,7 @@
     TEST_SVC_UUID = '12345678-1234-5678-1234-56789abcdef0'
 
     def __init__(self, bus, index):
-        Service.__init__(self, bus, index, self.TEST_SVC_UUID, False)
+        Service.__init__(self, bus, index, self.TEST_SVC_UUID, True)
         self.add_characteristic(TestCharacteristic(bus, 0, self))
         self.add_characteristic(TestEncryptCharacteristic(bus, 1, self))
         self.add_characteristic(TestSecureCharacteristic(bus, 2, self))