t9210: do not rely on lazy fetching to fail

With "rev-list --missing=print $start", where "$start" is a 40-hex
object name, the object may or may not be lazily fetched from the
promisor.  Make sure it fails by forcing dereference of "$start"
at that point.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9210-scalar.sh

@@ -154,7 +154,14 @@ test_expect_success 'scalar clone' '
 		test_cmp expect actual &&
 
 		test_path_is_missing 1/2 &&
-		test_must_fail git rev-list --missing=print $second &&
+
+		# This relies on the fact that the presence of "--missing"
+		# on the command line forces lazy fetching off before
+		# "$second^{blob}" gets parsed.  Without "^{blob}", a
+		# bare object name "$second" is taken into the queue and
+		# the command may not fail with a fixed "rev-list --missing".
+		test_must_fail git rev-list --missing=print "$second^{blob}" -- &&
+
 		git rev-list $second &&
 		git cat-file blob $second >actual &&
 		echo "second" >expect &&