ERROR:root:No module named _50_admin_add_monitoring_panel - Monasca UI integration with existing devstack

Integrating Monasca-UI with existing openstack environment like devstack throwing error "ERROR:root:No module named _50_admin_add_monitoring_panel"

Reproduce Error

1) install devstack - ocata version - without monasca plugin
2) Download monasca-ui from "git clone https://github.com/openstack/monasca-ui"

Do

ln -sf $(pwd)/../monasca-ui/monitoring/enabled/_50_admin_add_monitoring_panel.py \
    $(pwd)/openstack_dashboard/enabled/_50_admin_add_monitoring_panel.py
ln -sf $(pwd)/../monasca-ui/monitoring/conf/monitoring_policy.json \
    $(pwd)/openstack_dashboard/conf/monitoring_policy.json
ln -sfF $(pwd)/../monasca-ui/monitoring $(pwd)/monitoring

cd /opt/stack/horizon

run "./run_test.sh"

it will throw error as

Running Horizon application tests
nosetests horizon --nocapture --nologcapture --exclude-dir=horizon/conf/ --exclude-dir=horizon/test/customization --cover-package=horizon --cover-inclusive --all-modules --exclude-dir=openstack_dashboard/test/integration_tests --verbosity=1
Creating test database for alias 'default'...
......................................................................................................................................................................................SSSSSSS............
----------------------------------------------------------------------
Ran 201 tests in 8.882s

OK (SKIP=7)
<MagicMock name='handle()' id='139953300311376'><MagicMock name='handle()' id='139953306958800'>Destroying test database for alias 'default'...
Running openstack_dashboard tests
WARNING:root:Error importing openstack_dashboard.enabled._50_admin_add_monitoring_panel
ERROR:root:No module named _50_admin_add_monitoring_panel
Traceback (most recent call last):
  File "/opt/stack/horizon/openstack_dashboard/utils/settings.py", line 30, in import_submodules
    submodule = import_module(name)
  File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
ImportError: No module named _50_admin_add_monitoring_panel