[PATCH] diff: consolidate test helper script pieces.

There were duplicate script pieces to help comparing diff
output, which this patch consolidates into the t/diff-lib.sh
library.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

t/t4007-rename-3.sh

@@ -7,20 +7,7 @@ test_description='Rename interaction with pathspec.
 
 '
 . ./test-lib.sh
-
-_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
-sanitize_diff_raw='s/ '"$_x40"' '"$_x40"' \([A-Z]\)[0-9]*	/ X X \1#	/'
-compare_diff_raw () {
-    # When heuristics are improved, the score numbers would change.
-    # Ignore them while comparing.
-    # Also we do not check SHA1 hash generation in this test, which
-    # is a job for t0000-basic.sh
-
-    sed -e "$sanitize_diff_raw" <"$1" >.tmp-1
-    sed -e "$sanitize_diff_raw" <"$2" >.tmp-2
-    diff -u .tmp-1 .tmp-2 && rm -f .tmp-1 .tmp-2
-}
+. ../diff-lib.sh ;# test-lib chdir's into trash
 
 test_expect_success \
     'prepare reference tree' \