Put charm into its own venv

This adds the venv option to the layer configuration and removes the
custom install hook as it's no longer needed.

src/hooks/install

@@ -1,25 +0,0 @@
-#!/bin/bash
-# Wrapper to deal with newer Ubuntu versions that don't have py2 installed
-# by default.
-
-check_and_install() {
-    pkg="${1}"
-    if ! dpkg -s ${pkg} 2>&1 > /dev/null; then
-        apt-get -y install ${pkg}
-    fi
-}
-status-set maintenance "Install hook running"
-
-juju-log "Installing tox"
-check_and_install 'tox'
-
-declare -a DEPS=('libssl-dev' 'libffi-dev' 'apt' 'python3-netaddr' 'python3-netifaces' 'python3-pip' 'python3-yaml' 'python-cinderclient' 'python-glanceclient' 'python-heatclient' 'python-keystoneclient' 'python-neutronclient' 'python-novaclient' 'python-swiftclient' 'python-ceilometerclient' 'openvswitch-test' 'python3-cinderclient' 'python3-glanceclient' 'python3-heatclient' 'python3-keystoneclient' 'python3-neutronclient' 'python3-novaclient' 'python3-swiftclient' 'python3-ceilometerclient')
-
-
-PYTHON="python"
-
-for dep in ${DEPS[@]}; do
-    check_and_install ${dep}
-done
-
-exec ./hooks/install.real

src/hooks/install.real

@@ -1,19 +0,0 @@
-#!/usr/bin/env python3
-
-# Load modules from $CHARM_DIR/lib
-import sys
-sys.path.append('lib')
-
-from charms.layer import basic
-basic.bootstrap_charm_deps()
-basic.init_config_states()
-
-
-# This will load and run the appropriate @hook and other decorated
-# handlers from $CHARM_DIR/reactive, $CHARM_DIR/hooks/reactive,
-# and $CHARM_DIR/hooks/relations.
-#
-# See https://jujucharms.com/docs/stable/authors-charm-building
-# for more information on this pattern.
-from charms.reactive import main
-main()

src/layer.yaml

@@ -4,4 +4,8 @@ includes:
   - interface:rabbitmq
   - interface:keystone
   - interface:barbican-hsm-plugin
+options:
+  basic:
+    use_venv: True
+    include_system_packages: True
 repo: git@github.com:openstack-charmers/charm-barbican.git