Minor fixes to script/release to source env

script/release

@@ -5,6 +5,17 @@ set -e
 cd "$(dirname $0)"/..
 ROOT=$(pwd)
 
+if [ -z "$VENV_NAME" ]; then
+    VENV_NAME="env"
+fi
+
+ACTIVATE="$VENV_NAME/bin/activate"
+if [ ! -f "$ACTIVATE" ]; then
+    echo "$ACTIVATE does not exist, run ./script/bootstrap" >&2
+    exit 1
+fi
+. "$ACTIVATE"
+
 VERSION=$(grep __VERSION__ $ROOT/octodns/__init__.py | sed -e "s/.* = '//" -e "s/'$//")
 
 git tag -s v$VERSION -m "Release $VERSION"