git-gui: replace encoding binary with iso8859-1

git-gui currently configures some channels as '-encoding binary' when
the channel is not really binary (e.g, the channel is consumed as lines
of text).  In 8.6, '-encoding binary' is an alias for '-encoding
iso8859), but TIP 699 removes this alias for Tcl 9.0. Let's switch to
'-encoding iso8859-1' to be compatible across Tcl versions.

Signed-off-by: Mark Levedahl <mlevedahl@gmail.com>

lib/blame.tcl

@@ -985,7 +985,7 @@ method _showcommit {cur_w lno} {
 			set msg {}
 			catch {
 				set fd [git_read [list cat-file commit $cmit]]
-				fconfigure $fd -encoding binary -translation lf
+				fconfigure $fd -encoding iso8859-1 -translation lf
 				# By default commits are assumed to be in utf-8
 				set enc utf-8
 				while {[gets $fd line] > 0} {

lib/commit.tcl

@@ -28,7 +28,7 @@ You are currently in the middle of a merge that has not been fully completed.  Y
 			set name ""
 			set email ""
 			set fd [git_read [list cat-file commit $curHEAD]]
-			fconfigure $fd -encoding binary -translation lf
+			fconfigure $fd -encoding iso8859-1 -translation lf
 			# By default commits are assumed to be in utf-8
 			set enc utf-8
 			while {[gets $fd line] > 0} {
@@ -361,7 +361,7 @@ proc commit_committree {fd_wt curHEAD msg_p} {
 	#
 	if {$commit_type eq {normal}} {
 		set fd_ot [git_read [list cat-file commit $PARENT]]
-		fconfigure $fd_ot -encoding binary -translation lf
+		fconfigure $fd_ot -encoding iso8859-1 -translation lf
 		set old_tree [gets $fd_ot]
 		close $fd_ot