[jb] Avoid failure to start when app is blacklisted

File "/usr/share/hue/desktop/core/src/desktop/urls.py", line 50, in <module>
from desktop.configuration import api as desktop_configuration_api
File "/usr/share/hue/desktop/core/src/desktop/configuration/api.py", line 32, in <module>
from notebook.connectors.hiveserver2 import HiveConfiguration, ImpalaConfiguration
File "/usr/share/hue/desktop/libs/notebook/src/notebook/connectors/hiveserver2.py", line 79, in <module>
from jobbrowser.views import get_job
File "/usr/share/hue/apps/jobbrowser/src/jobbrowser/views.py", line 64, in <module>
from jobbrowser.api import get_api, ApplicationNotRunning, JobExpired
File "/usr/share/hue/apps/jobbrowser/src/jobbrowser/api.py", line 38, in <module>
from jobbrowser.yarn_models import Application, YarnV2Job, Job as YarnJob, KilledJob as KilledYarnJob, Container, SparkJob
File "/usr/share/hue/apps/jobbrowser/src/jobbrowser/yarn_models.py", line 44, in <module>
from jobbrowser.models import format_unixtime_ms
File "/usr/share/hue/apps/jobbrowser/src/jobbrowser/models.py", line 85, in <module>
class HiveQuery(models.Model):
File "/usr/share/hue/build/env/local/lib/python2.7/site-packages/Django-1.11.29-py2.7.egg/django/db/models/base.py", line 118, in _new_
"INSTALLED_APPS." % (module, name)
RuntimeError: Model class jobbrowser.models.HiveQuery doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS.