Fix two flake8 errors

powerline/lint/__init__.py

@@ -604,7 +604,7 @@ def check_segment_name(name, data, context, echoerr):
 			except AttributeError:
 				echoerr(context='Error while loading segment function (key {key})'.format(key=context_key(context)),
 						problem='failed to load function {0} from module {1}'.format(name, module),
-						problem_mark=match_name.mark)
+						problem_mark=name.mark)
 				return True, False, True
 
 		if not callable(func):

powerline/lint/markedjson/reader.py

@@ -88,7 +88,6 @@ class Reader(object):
 	def check_printable(self, data):
 		match = NON_PRINTABLE.search(data)
 		if match:
-			character = match.group()
 			self.update_pointer(match.start())
 			raise ReaderError('while reading from stream', None,
 					'found special characters which are not allowed',