fix misspelling. IPython <-> BPython

--no-ipython's help: BPython -> IPython
--no-bpython's help: IPython -> BPython

Author: item4

flask_script/commands.py

@@ -260,12 +260,12 @@ def get_options(self):
                 action="store_true",
                 dest='no_ipython',
                 default=not(self.use_ipython),
-                help="Do not use the BPython shell"),
+                help="Do not use the IPython shell"),
             Option('--no-bpython',
                 action="store_true",
                 dest='no_bpython',
                 default=not(self.use_bpython),
-                help="Do not use the IPython shell"),
+                help="Do not use the BPython shell"),
         )
 
     def get_context(self):