Clear out the python class name in OptionParsingStarted for the OptionGroupPythonClassWithDict

options class.  This value was hanging around so for instance if you made a scripted breakpoint
resolver, then went to set another breakpoint, it would still think you had passed in a class
name and the breakpoint wouldn't do what you expected.

lldb/source/Interpreter/OptionGroupPythonClassWithDict.cpp

@@ -127,6 +127,7 @@ void OptionGroupPythonClassWithDict::OptionParsingStarting(
   // the user didn't pass any -k -v pairs.  We want to be able to warn if these
   // were passed when the function they passed won't use them.
   m_dict_sp.reset();
+  m_name.clear();
 }
 
 Status OptionGroupPythonClassWithDict::OptionParsingFinished(