* Better output for disambiguate_specs()
* Fix wrong exception name.
* Fix satsifies(): concrete specs require matching by hash.
- Fixes uninstall by hash and other places where we need to match a
specific spec.
- Fix an error in provider_index (satisfies() call was backwards)
- Fix an error in satisfies_dependencies(): checks were too shallow.
* Fix default args in Spec.tree()
* Move installed_dependents() to DB to avoid unknown package error.
* Make `spack find` and `sapck.store.db.query()` faster for hashes.
* Add a test to ensure satisfies() respects concrete Specs' hashes.
a2b4146e10