python3: bump to version 3.7.1

This change bumps Python3 version to 3.7.1.
Patch `002-fix-implicit-dh-free-declaration.patch` is now included in
upstream.
This also fixes CVE-2018-1061.
   https://www.cvedetails.com/cve/CVE-2018-1061/

Compile & run-tested on x86.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

lang/python/python3/patches/002-fix-implicit-dh-free-declaration.patch

@@ -1,12 +0,0 @@
-diff --git a/Modules/_ssl.c b/Modules/_ssl.c
-index 2bce4816d2..3c93884809 100644
---- a/Modules/_ssl.c
-+++ b/Modules/_ssl.c
-@@ -63,6 +63,7 @@ static PySocketModule_APIObject PySocketModule;
- #include "openssl/err.h"
- #include "openssl/rand.h"
- #include "openssl/bio.h"
-+#include "openssl/dh.h"
- 
- #ifndef HAVE_X509_VERIFY_PARAM_SET1_HOST
- #  ifdef LIBRESSL_VERSION_NUMBER