The object database layer has been simplified by eagerly loading
alternate object directories upon initialization, instead of
deferring it to the first object lookup. This eliminates the need
for scattered lazy-loading calls throughout the codebase and paves
the way for integrating alternates with the pluggable backends.
* ps/odb-eagerly-load-alternates:
odb: drop `alternates_db` field
odb: drop `loaded_alternates` field
odb: eagerly initialize alternates
odb: decouple source path comparisons from `the_repository`
setup: create ref and object databases after config is written
a431cd5887