In tree view, by default, hash_base is HEAD and hash is the
entry equivalent.  Else the user had selected a hash_base or
hash, say by clicking on a revision or commit, in which case
those values are used.
Signed-off-by: NLuben Tuikov <ltuikov@yahoo.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>