Fix Alarms class filter

Не работал фильтр на несколько классов аварий. При попытке выбрать несколько классов, получали трейс

EXCEPTION: <class 'RuntimeError'> dictionary changed size during iteration
START OF TRACEBACK
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File: services/web/apps/fm/alarm/views.py (Line: 142)
Function: cleaned_query
  135                 self.query_param,
  136                 self.only_param,
  137             ):
  138                 if p in q:
  139                     del q[p]
  140             # Extract IN
  141             # extjs not working with same parameter name in query
  142 ==>         for p in q:
  143                 if p.endswith("__in") and self.rx_oper_splitter.match(p):
  144                     field = self.rx_oper_splitter.match(p).group("field") + "__in"
  145                     if field not in q:
  146                         q[field] = [q[p]]
  147                     else:
  148                         q[field] += [q[p]]
Variables:
               field = 'alarm_class__in'
                   p = 'alarm_class1__in'
              status = 'A'
                   q = 
{'alarm_class__in': ['594e712725aecf6d5e72233c', '58d281ed25aecf1d5c8b8cfc'],
 'collapse': '1',
 'maintenance': 'hide'}
                self = 
<noc.services.web.apps.fm.alarm.views.AlarmApplication object at 0x7f8c56e407f0>