Revert "Start Cat tests from 2 as onedrive doesn't support ranging from 1"

Now that https://github.com/OneDrive/onedrive-api-docs/issues/543 is
fixed, this can be reverted.

This reverts commit 320c53eab0d86095d4854fbb80097b5b05bb0ece.

fs/operations_test.go

@@ -704,7 +704,7 @@ func TestCat(t *testing.T) {
 		{0, -1, "ABCDEFGHIJ", "012345678"},
 		{0, 5, "ABCDE", "01234"},
 		{-3, -1, "HIJ", "678"},
-		{2, 3, "CDE", "234"},
+		{1, 3, "BCD", "123"},
 	} {
 		var buf bytes.Buffer
 		err := fs.Cat(r.fremote, &buf, test.offset, test.count)