Revert "global: call config observers on global_init (and start logging!)"

This reverts commit a30917746614275baeb718e902133f06ef44fba6. This commit
includes calls that involve Mutexes, Lockers, and lockdep -- which isn't
yet set up, so things break horribly. A more subtle approach is required.

Signed-off-by: Greg Farnum <greg@inktank.com>