fix import uwsgi only when app start with uwsgi

alignak_backend/app.py

@@ -19,7 +19,6 @@
 import time
 import traceback
 import uuid
-import uwsgi
 from collections import OrderedDict
 from datetime import datetime, timedelta
 from future.utils import iteritems
@@ -1463,7 +1462,13 @@ def get_settings(prev_settings):
 jobs = []
 # run only sheduler on uwsgi worker 1, because option lazy-apps in uwsgi will run the
 # scheduler on each worker and we don't want that ;)
-if uwsgi.worker_id() == 1:
+try:
+    import uwsgi
+    worker_id = uwsgi.worker_id()
+except ImportError:
+    worker_id = 1
+
+if worker_id == 1:
     if settings['SCHEDULER_TIMESERIES_ACTIVE']:
         jobs.append(
             {