Remove try/catch and directly use six.next

Author: deveshks

src/pip/_internal/utils/misc.py

@@ -545,13 +545,10 @@ def __init__(self, lines):
 
     def readline(self):
         try:
-            try:
-                return next(self._gen)
-            except NameError:
-                # flake8-bugbear B305 suggests using six.next for
-                # Python 2 compatibility. This along with the try/except
-                # block can be removed once we drop Python 2 support
-                return six.next(self._gen)
+            # six.next allows for both Python 2 and 3 compatibility
+            # It should be changed to next() builtin when we drop
+            # python 2 support
+            return six.next(self._gen)
         except StopIteration:
             return ''