Sync with v1.8.2.3

* maint:
  Git 1.8.2.3
  t5004: avoid using tar for checking emptiness of archive
  t5004: ignore pax global header file
  mergetools/kdiff3: do not use --auto when diffing
  transport-helper: trivial style cleanup

mergetools/kdiff3

@@ -1,5 +1,5 @@
 diff_cmd () {
-	"$merge_tool_path" --auto \
+	"$merge_tool_path" \
 		--L1 "$MERGED (A)" --L2 "$MERGED (B)" \
 		"$LOCAL" "$REMOTE" >/dev/null 2>&1
 }