extensions: use [0:1] slice on config path instead of [0]
This behaves the same in Python 2 and Python 3, even though the path
is a bytes.
--- a/mercurial/extensions.py Fri Mar 03 13:27:21 2017 -0500
+++ b/mercurial/extensions.py Fri Mar 03 13:32:10 2017 -0500
@@ -160,7 +160,7 @@
newindex = len(_order)
for (name, path) in result:
if path:
- if path[0] == '!':
+ if path[0:1] == '!':
_disabledextensions[name] = path[1:]
continue
try: