Fix redundant UTF-8 check

In the file proxy/server.py, handle_request method does UTF-8
check twice. This patch is to fix it.

Change-Id: I6db742bce6fa4fa9e935b15460037e0ec90e9373
Closes-Bug: #1704539

swift/proxy/server.py

@@ -26,7 +26,6 @@ import functools
 import sys
 
 from eventlet import Timeout
-import six
 
 from swift import __canonical_version__ as swift_version
 from swift.common import constraints
@@ -462,9 +461,6 @@ class Application(object):
 
             try:
                 controller, path_parts = self.get_controller(req)
-                p = req.path_info
-                if isinstance(p, six.text_type):
-                    p = p.encode('utf-8')
             except APIVersionError:
                 self.logger.increment('errors')
                 return HTTPBadRequest(request=req)