Update Python 3.5.8 xz checksum (#1442)

```
checksum mismatch: Python-3.5.8.tar.xz (file is corrupt)
expected 1bb1319bcd05d95c4d9752c7f6378c5378b8f467fb9045e07023e94b28b2ff41, got 55a345c78ee3afbc2e60678442aad7bcc384ddea5bb95f8d66edc4868d4847d4
```

plugins/python-build/share/python-build/3.5.8

@@ -3,7 +3,7 @@ prefer_openssl11
 install_package "openssl-1.1.0j" "https://www.openssl.org/source/openssl-1.1.0j.tar.gz#31bec6c203ce1a8e93d5994f4ed304c63ccf07676118b6634edded12ad1b3246" mac_openssl --if has_broken_mac_openssl
 install_package "readline-8.0" "https://ftpmirror.gnu.org/readline/readline-8.0.tar.gz#e339f51971478d369f8a053a330a190781acb9864cf4c541060f12078948e461" mac_readline --if has_broken_mac_readline
 if has_tar_xz_support; then
-  install_package "Python-3.5.8" "https://www.python.org/ftp/python/3.5.8/Python-3.5.8.tar.xz#1bb1319bcd05d95c4d9752c7f6378c5378b8f467fb9045e07023e94b28b2ff41" ldflags_dirs standard verify_py35 ensurepip
+  install_package "Python-3.5.8" "https://www.python.org/ftp/python/3.5.8/Python-3.5.8.tar.xz#55a345c78ee3afbc2e60678442aad7bcc384ddea5bb95f8d66edc4868d4847d4" ldflags_dirs standard verify_py35 ensurepip
 else
   install_package "Python-3.5.8" "https://www.python.org/ftp/python/3.5.8/Python-3.5.8.tgz#18c88dfd260147bc7247e6356010e5d4916dfbfc480f6434917f88e61228177a" ldflags_dirs standard verify_py35 ensurepip
 fi