t5000, t5003: simplify commit

Add the whole directory of test files at once using git add instead of
calling git update-index on each of them and use git commit instead of
the plumbing commands write-tree, update-ref and commit-tree to build
the commit.  This simplifies the code considerably.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5000-tar-tree.sh

@@ -119,14 +119,10 @@ test_expect_success \
     'echo ignore me >a/ignored &&
      echo ignored export-ignore >.git/info/attributes'
 
-test_expect_success \
-    'add files to repository' \
-    'find a -type f | xargs git update-index --add &&
-     find a -type l | xargs git update-index --add &&
-     treeid=$(git write-tree) &&
-     echo $treeid >treeid &&
-     git update-ref HEAD $(TZ=GMT GIT_COMMITTER_DATE="2005-05-27 22:00:00" \
-     git commit-tree $treeid </dev/null)'
+test_expect_success 'add files to repository' '
+	git add a &&
+	GIT_COMMITTER_DATE="2005-05-27 22:00" git commit -m initial
+'
 
 test_expect_success 'setup export-subst' '
 	echo "substfile?" export-subst >>.git/info/attributes &&

t/t5003-archive-zip.sh

@@ -61,14 +61,10 @@ test_expect_success \
     'echo ignore me >a/ignored &&
      echo ignored export-ignore >.git/info/attributes'
 
-test_expect_success \
-    'add files to repository' \
-    'find a -type f | xargs git update-index --add &&
-     find a -type l | xargs git update-index --add &&
-     treeid=`git write-tree` &&
-     echo $treeid >treeid &&
-     git update-ref HEAD $(TZ=GMT GIT_COMMITTER_DATE="2005-05-27 22:00:00" \
-     git commit-tree $treeid </dev/null)'
+test_expect_success 'add files to repository' '
+	git add a &&
+	GIT_COMMITTER_DATE="2005-05-27 22:00" git commit -m initial
+'
 
 test_expect_success 'setup export-subst' '
 	echo "substfile?" export-subst >>.git/info/attributes &&