VOL-528: Delete of an OLT in the pre-provisioning state

Change-Id: Ia1496fe655c5b18e1036146bfb456906964937fa
diff --git a/voltha/core/local_handler.py b/voltha/core/local_handler.py
index 26016ed..55a0cfc 100644
--- a/voltha/core/local_handler.py
+++ b/voltha/core/local_handler.py
@@ -704,7 +704,7 @@
         try:
             path = '/devices/{}'.format(request.id)
             device = self.root.get(path)
-            assert device.admin_state == AdminState.DISABLED, \
+            assert device.admin_state == AdminState.DISABLED or device.admin_state == AdminState.PREPROVISIONED, \
                 'Device to delete cannot be ' \
                 'in admin state \'{}\''.format(device.admin_state)
             assert not device.type.endswith("_onu"), \