Replace curly quotes with straight quotes

Curly quotes usually input from Chinese input method.
When read from english context, it makes some confusion.

Change-Id: I46c0c3bfc49fb657eb5c6fbad24682f1d579a121
diff --git a/tox.ini b/tox.ini
index d7801db..d5e3b91 100644
--- a/tox.ini
+++ b/tox.ini
@@ -59,11 +59,11 @@
 commands = oslo-config-generator --config-file etc/config-generator.patrole.conf
 
 [flake8]
-# [H106] Don’t put vim configuration in source files.
+# [H106] Don't put vim configuration in source files.
 # [H203] Use assertIs(Not)None to check for None.
 # [H204] Use assert(Not)Equal to check for equality.
 # [H205] Use assert(Greater|Less)(Equal) for comparison.
-# [H210] Require ‘autospec’, ‘spec’, or ‘spec_set’ in mock.patch/mock.patch.object calls
+# [H210] Require 'autospec', 'spec', or 'spec_set' in mock.patch/mock.patch.object calls
 # [H904] Delay string interpolations at logging calls.
 enable-extensions = H106,H203,H204,H205,H210,H904
 show-source = True