t4205: sort log output in a hash-independent way

t4205: sort log output in a hash-independent way

This test enumerates log entries and then sorts them.  For SHA-1, this
produces results that happen to sort in the order specified in the test,
but for other hash algorithms they sort differently.  Ensure we sort the
log entries in a hash-independent way by sorting on the ref name instead
of the object ID.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>