Merge branch 'jt/binsearch-with-fanout'

Refactor the code to binary search starting from a fan-out table
(which is how the packfile is indexed with object names) into a
reusable helper.

* jt/binsearch-with-fanout:
packfile: refactor hash search with fanout table
packfile: remove GIT_DEBUG_LOOKUP log statements

diff --cc packfile.c
Simple merge