pylint: Fix consider-iterating-dictionary

> Emitted when the keys of a dictionary are iterated through the
  ``.keys()`` method or when ``.keys()`` is used for a membership check.
  It is enough to iterate through the dictionary itself, ``for key in
  dictionary``. For membership checks, ``if key in dictionary`` is faster.

See pylint-dev/pylint#4069

Fixes: fleet-commander#279
Signed-off-by: Stanislav Levin <slev@altlinux.org>

admin/fleetcommander/database.py

@@ -98,7 +98,7 @@ def __setitem__(self, key, value):
             self.__delitem__(key)
 
         valuetype = type(value).__name__
-        if valuetype not in list(self._SUPPORTED_TYPES.keys()):
+        if valuetype not in self._SUPPORTED_TYPES:
             raise ValueError("Type %s is not supported by SQLiteDict" % valuetype)
 
         if valuetype in self._SERIALIZED_TYPES: