access android source via https protocol

Update: no need to use this trick anymore, since google has changed the default protocol to https.

---

repo is a good tool for android source tree management. It manages all git repositories for all android subprojects. By default, it clones these project via git: protocol, which is more efficient to work with than http. But the git: protocol accesses 9418 port, which may be blocked by firewalls, especially when we're using it within a restricted network environment. In this case, it's desired to be able to access android source tree with http: protocol.
The site kernel.org that hosts android source code supports https: protocol, so we can change the config file in .git folder for each android subproject to force using https: protocol. The bash command below does the job:
find -regex ".*.git/config" -exec sed -i s/git:/https:/ {} \;
To change it back to git protocol, exchange git: and https: in the command.