tests: fix run-tests environment cleanup on Python 3
Differential Revision: https://phab.mercurial-scm.org/D2521
--- a/tests/run-tests.py Sun Feb 25 16:14:37 2018 +0900
+++ b/tests/run-tests.py Thu Mar 01 15:46:21 2018 -0500
@@ -1087,7 +1087,7 @@
del env[k]
# unset env related to hooks
- for k in env.keys():
+ for k in list(env):
if k.startswith('HG_'):
del env[k]