git-gui: remove option --stderr from git_read

Some callers of git_read want to redirect stderr of the invoked command
to stdout.  The function offers option --stderr for this purpose.
However, the option only appends 2>@1 to the commands.  The callers can
do that themselves. In lib/console.tcl we even have a caller that
already knew implictly what --stderr does behind the scenes.

This is a preparation for a later change where we want to make git_read
non-variadic. Then it cannot have optional leading arguments.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Taylor Blau <me@ttaylorr.com>

git-gui.sh

@@ -651,10 +651,6 @@ proc git_read {args} {
 			_lappend_nice opt
 		}
 
-		--stderr {
-			lappend args 2>@1
-		}
-
 		default {
 			break
 		}

lib/checkout_op.tcl

@@ -345,13 +345,14 @@ method _readtree {} {
 		[mc "Updating working directory to '%s'..." [_name $this]] \
 		[mc "files checked out"]]
 
-	set fd [git_read --stderr read-tree \
+	set fd [git_read read-tree \
 		-m \
 		-u \
 		-v \
 		--exclude-per-directory=.gitignore \
 		$HEAD \
 		$new_hash \
+		2>@1 \
 		]
 	fconfigure $fd -blocking 0 -translation binary
 	fileevent $fd readable [cb _readtree_wait $fd $status_bar_operation]

lib/choose_repository.tcl

@@ -953,12 +953,13 @@ method _do_clone_checkout {HEAD} {
 		[mc "files"]]
 
 	set readtree_err {}
-	set fd [git_read --stderr read-tree \
+	set fd [git_read read-tree \
 		-m \
 		-u \
 		-v \
 		HEAD \
 		HEAD \
+		2>@1 \
 		]
 	fconfigure $fd -blocking 0 -translation binary
 	fileevent $fd readable [cb _readtree_wait $fd]

lib/console.tcl

@@ -91,10 +91,10 @@ method _init {} {
 }
 
 method exec {cmd {after {}}} {
-	if {[lindex $cmd 0] eq {git}} {
-		set fd_f [eval git_read --stderr [lrange $cmd 1 end]]
-	} else {
 	lappend cmd 2>@1
+	if {[lindex $cmd 0] eq {git}} {
+		set fd_f [eval git_read [lrange $cmd 1 end]]
+	} else {
 		set fd_f [_open_stdout_stderr $cmd]
 	}
 	fconfigure $fd_f -blocking 0 -translation binary

lib/merge.tcl

@@ -239,7 +239,7 @@ Continue with resetting the current changes?"]
 	}
 
 	if {[ask_popup $op_question] eq {yes}} {
-		set fd [git_read --stderr read-tree --reset -u -v HEAD]
+		set fd [git_read read-tree --reset -u -v HEAD 2>@1]
 		fconfigure $fd -blocking 0 -translation binary
 		set status_bar_operation [$::main_status \
 			start \