Revert "GitRepository/add_remote_repo: fix the 'tags' argument"

Which caused an unwanted behavior of not fetching refs/heads at all --
only tags were fetched.

This reverts commit 5dd598fb8f2a9109189fad6cf631811f12ce2130

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Remove tests now covered by 18_test_Config