When NM was registering all of its enum types by hand, it was using
NamesLikeThis rather than the default names-like-this for the "nick"
values. When we switched to using glib-mkenums, this resulted in
dbus-glib using different strings for the D-Bus error names, causing
compatibility problems.

Fix this by using glib-mkenums annotations to manually fix all the
enum values back to what they were before. (This can't be done in a
more automated way, because the old names aren't 100% consistent. Eg,
"UNKNOWN" frequently becomes "UnknownError" rather than just
"Unknown".)