check-code: exclude demandimport.py and policy.py from Python 3 checks

These modules can't depend on pycompat.py, which means we have to write Py3
hacks in them.

contrib/check-code.py

@@ -492,8 +492,8 b' py3pats = ['
 checks = [
     ('python', r'.*\.(py|cgi)$', r'^#!.*python', pyfilters, pypats),
     ('python', r'.*hgext.*\.py$', '', [], pyextnfpats),
-    ('python 3', r'.*(hgext|mercurial)/(?!pycompat).*\.py', '',
-            pyfilters, py3pats),
+    ('python 3', r'.*(hgext|mercurial)/(?!demandimport|policy|pycompat).*\.py',
+     '', pyfilters, py3pats),
     ('test script', r'(.*/)?test-[^.~]*$', '', testfilters, testpats),
     ('c', r'.*\.[ch]$', '', cfilters, cpats),
     ('unified test', r'.*\.t$', '', utestfilters, utestpats),

tests/test-check-code.t

@@ -13,9 +13,6 b' New errors are not allowed. Warnings are'
    >             r.revision(r.node(x))
    don't convert rev to node before passing to revision(nodeorrev)
   Skipping i18n/polib.py it has no-che?k-code (glob)
-  mercurial/demandimport.py:314:
-   >     if os.environ.get('HGDEMANDIMPORT') != 'disable':
-   use encoding.environ instead (py3)
   mercurial/encoding.py:54:
    >     environ = os.environ
    use encoding.environ instead (py3)
@@ -30,15 +27,6 b' New errors are not allowed. Warnings are'
    use encoding.environ instead (py3)
   Skipping mercurial/httpclient/__init__.py it has no-che?k-code (glob)
   Skipping mercurial/httpclient/_readers.py it has no-che?k-code (glob)
-  mercurial/policy.py:46:
-   >     if 'HGMODULEPOLICY' in os.environ:
-   use encoding.environ instead (py3)
-  mercurial/policy.py:47:
-   >         policy = os.environ['HGMODULEPOLICY'].encode('utf-8')
-   use encoding.environ instead (py3)
-  mercurial/policy.py:49:
-   >     policy = os.environ.get('HGMODULEPOLICY', policy)
-   use encoding.environ instead (py3)
   Skipping mercurial/statprof.py it has no-che?k-code (glob)
   Skipping tests/badserverext.py it has no-che?k-code (glob)
   [1]