Revert "Remove vendored libjuju"

This reverts commit 9d18c22a0dc9e295adda50601fc5e2f45d2c9b8a.

Change-Id: I7dbf291ccd750c5f836ff80c642be492434ab3ac
Signed-off-by: Adam Israel <adam.israel@canonical.com>
diff --git a/modules/libjuju/juju/exceptions.py b/modules/libjuju/juju/exceptions.py
new file mode 100644
index 0000000..bcf07b6
--- /dev/null
+++ b/modules/libjuju/juju/exceptions.py
@@ -0,0 +1,2 @@
+class DeadEntityException(Exception):
+    pass