setup: don't support py 3.5.0, 3.5.1, 3.5.2 because of bug in codecs

codecs.escape_encode() raises SystemError if an empty bytestring is passed. We
do that at some places in our code and because of this bug, things break.
Therefore we can't support the mentioned version. The bug was fixed in 3.5.3,
3.6.0 beta 2. We can't support 3.6.0 anyway because of bug in formatting
bytestrings.

Link to the python bug: https://bugs.python.org/issue25270

Differential Revision: https://phab.mercurial-scm.org/D4475

setup.py

@@ -11,6 +11,9 b" if os.environ.get('HGALLOWPYTHON3', ''):"
     # Mercurial will never work on Python 3 before 3.5 due to a lack
     # of % formatting on bytestrings, and can't work on 3.6.0 or 3.6.1
     # due to a bug in % formatting in bytestrings.
+    # We cannot support Python 3.5.0, 3.5.1, 3.5.2 because of bug in
+    # codecs.escape_encode() where it raises SystemError on empty bytestring
+    # bug link: https://bugs.python.org/issue25270
     #
     # TODO: when we actually work on Python 3, use this string as the
     # actual supportedpy string.
@@ -21,6 +24,9 b" if os.environ.get('HGALLOWPYTHON3', ''):"
         '!=3.2.*',
         '!=3.3.*',
         '!=3.4.*',
+        '!=3.5.0',
+        '!=3.5.1',
+        '!=3.5.2',
         '!=3.6.0',
         '!=3.6.1',
     ])