python3: Upgrade 3.7.4 -> 3.7.5

Backported patch removed.

3.7.5 also includes the fix for CVE-2019-16935.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>