remove all mongodb related code

freqtrade/arguments.py

@@ -203,12 +203,6 @@ class Arguments(object):
             type=int,
             metavar='INT',
         )
-        parser.add_argument(
-            '--use-mongodb',
-            help='parallelize evaluations with mongodb (requires mongod in PATH)',
-            dest='mongodb',
-            action='store_true',
-        )
         parser.add_argument(
             '-s', '--spaces',
             help='Specify which parameters to hyperopt. Space separate list. \