Update contributing instructions

Point contributors to the correct launchpad page.

Change-Id: I4ce980a8957a186ec3e1b4be2e0ee3ecf333b849
Fixed typo in docstring for _get_config_dirs

The docstring for function _get_config_dirs() refers to directories
as "directors".

Change-Id: Iede3934a9712de98dc1f39604d5dc210fbfc4672
Merge "Fixed typo in docstring for _get_config_dirs"
Merge "Update contributing instructions"