Update libjuju

- fix licensing quirks
- refresh against libjuju master

Signed-off-by: Adam Israel <adam.israel@canonical.com>
diff --git a/modules/libjuju/tests/integration/test_machine.py b/modules/libjuju/tests/integration/test_machine.py
index 60de035..cabf46d 100644
--- a/modules/libjuju/tests/integration/test_machine.py
+++ b/modules/libjuju/tests/integration/test_machine.py
@@ -28,7 +28,8 @@
 
         await asyncio.wait_for(
             model.block_until(lambda: (machine.status == 'running' and
-                                       machine.agent_status == 'started')),
+                                       machine.agent_status == 'started' and
+                                       machine.agent_version is not None)),
             timeout=480)
 
         assert machine.status == 'running'