python3: update to version 3.6.9

3.6.9 is the latest security fix release of Python 3.6.

- Fixes: CVE-2018-20852, CVE-2019-9948, CVE-2019-9740, CVE-2019-5010
- Refreshed patches
- Removed a few backports patches

Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>

lang/python/python3/patches/015-abort-on-failed-modules.patch

@@ -1,6 +1,6 @@
 --- a/setup.py
 +++ b/setup.py
-@@ -333,6 +333,7 @@ class PyBuildExt(build_ext):
+@@ -338,6 +338,7 @@ class PyBuildExt(build_ext):
              print("Failed to build these modules:")
              print_three_column(failed)
              print()