Adjust VNI column for provisioner to text

Allows the storing of the textual cluster labels (e.g. 'upstream') as
valid VNI values in the template.

api-daemon/pvcapid/models.py

@@ -78,6 +78,7 @@ class DBNetworkElement(db.Model):
     id = db.Column(db.Integer, primary_key=True)
     network_template = db.Column(db.Integer, db.ForeignKey("network_template.id"), nullable=False)
     vni = db.Column(db.Integer, nullable=False)
+    vni2 = db.Column(db.Text, nullable=False)
 
     def __init__(self, network_template, vni):
         self.network_template = network_template