quotaholder: Explicitly set commission's issue_time

Avoid function call as a default value in model.

snf-astakos-app/astakos/quotaholder/callpoint.py

@@ -164,7 +164,9 @@ def issue_commission(clientkey, provisions, name="", force=False):
         operations.revert()
         raise
 
-    commission = Commission.objects.create(clientkey=clientkey, name=name)
+    commission = Commission.objects.create(clientkey=clientkey,
+                                           name=name,
+                                           issue_time=now())
     for (holder, source, resource), quantity in provisions_to_create:
         Provision.objects.create(serial=commission,
                                  holder=holder,

snf-astakos-app/astakos/quotaholder/models.py

@@ -65,7 +65,7 @@ class Commission(Model):
     serial = AutoField(primary_key=True)
     name = CharField(max_length=4096, default="")
     clientkey = CharField(max_length=4096, null=False)
-    issue_time = CharField(max_length=24, default=now)
+    issue_time = CharField(max_length=24)
 
     objects = ForUpdateManager()