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/docs/api/juju.errors.rst b/modules/libjuju/docs/api/juju.errors.rst
new file mode 100644
index 0000000..7c77574
--- /dev/null
+++ b/modules/libjuju/docs/api/juju.errors.rst
@@ -0,0 +1,13 @@
+juju.errors
+===========
+
+.. rubric:: Summary
+
+.. automembersummary:: juju.errors
+
+.. rubric:: Reference
+
+.. automodule:: juju.errors
+    :members:
+    :undoc-members:
+    :show-inheritance: