Revert "Update gitconfig to use gnome-keyring"

This reverts commit c78b23d95ef4f0c1afac50d6e91ba0c96e930d2d.
Revert "Use /usr/bin/thunderbird instead of /usr/local/bin… in xbindkysrc"

This reverts commit 1ad862514201ecec3ed53bee782f5d40603b025c.