New N2VC interface + updated libjuju

This commit introduces the Python3 N2VC module, which acts as a standard
interface to the VCA.

The goal of this is to provide a common way for modules to interface
with the VCA.

- Updated libjuju from 0.6.1 to 0.7.3

Signed-off-by: Adam Israel <adam.israel@canonical.com>
Change-Id: Ide70fb5ae5797eb6486de24653dc09a23f9c009e
diff --git a/modules/libjuju/Makefile b/modules/libjuju/Makefile
index 2e59306..bd59a97 100644
--- a/modules/libjuju/Makefile
+++ b/modules/libjuju/Makefile
@@ -1,5 +1,5 @@
-BIN := .tox/py35/bin
-PY := $(BIN)/python3.5
+BIN := .tox/py3/bin
+PY := $(BIN)/python
 PIP := $(BIN)/pip
 SCHEMAGEN := $(shell which schemagen)
 VERSION=$(shell cat VERSION)
@@ -29,10 +29,10 @@
 	cd docs/_build/ && zip -r docs.zip *
 
 release:
-	git remote | xargs -L1 git fetch --tags
+	git fetch --tags
 	$(PY) setup.py sdist upload
 	git tag ${VERSION}
-	git remote | xargs -L1 git push --tags
+	git push --tags
 
 upload: release