gitRepo: Rewrite the "urllib.request.urlopen" patch for Python 3

The old variant is still working but setting "cafile" is deprecated
since version 3.6 [0] and generates a warning:
DeprecationWarning: cafile, capath and cadefault are deprecated, use a custom context instead.

But without this patch "fetchRepoProject" still fails with
"error no host given" (see 337380ea1d).

[0]: https://docs.python.org/3.7/library/urllib.request.html#urllib.request.urlopen

pkgs/applications/version-management/git-repo/import-ssl-module.patch

@@ -0,0 +1,10 @@
+--- a/repo	2020-02-05 21:11:52.773854798 +0100
++++ b/repo	2020-02-05 21:12:34.018329462 +0100
+@@ -137,6 +137,7 @@
+ import stat
+ import subprocess
+ import sys
++import ssl
+ 
+ if sys.version_info[0] == 3:
+   import urllib.request