git-gui: When calling post-commit hook wrong variable was cleared.

Before calling the post-commit hook, the variable "pc_err" is cleared
while later only "pch_error" is used. "pch_error$cmt_id" only appeared in
"upvar"-Statements (which were changed to "global") and was removed.

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

lib/commit.tcl

@@ -407,8 +407,8 @@ A rescan will be automatically started now.
 	#
 	set fd_ph [githook_read post-commit]
 	if {$fd_ph ne {}} {
-		upvar #0 pch_error$cmt_id pc_err
-		set pc_err {}
+		global pch_error
+		set pch_error {}
 		fconfigure $fd_ph -blocking 0 -translation binary -eofchar {}
 		fileevent $fd_ph readable \
 			[list commit_postcommit_wait $fd_ph $cmt_id]
@@ -470,7 +470,7 @@ A rescan will be automatically started now.
 }
 
 proc commit_postcommit_wait {fd_ph cmt_id} {
-	upvar #0 pch_error$cmt_id pch_error
+	global pch_error
 
 	append pch_error [read $fd_ph]
 	fconfigure $fd_ph -blocking 1