The test scenario doesn't require the same image, instead it focuses on
the duplicated node-name, so use null-co to avoid locking conflict.

Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 tests/qemu-iotests/087 | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/tests/qemu-iotests/087 b/tests/qemu-iotests/087
index 9de57dd..6d52f7d 100755
--- a/tests/qemu-iotests/087
+++ b/tests/qemu-iotests/087
@@ -82,8 +82,7 @@ run_qemu -drive driver=$IMGFMT,id=disk,node-name=test-node,file="$TEST_IMG" <<EO
       "driver": "$IMGFMT",
       "node-name": "disk",
       "file": {
-          "driver": "file",
-          "filename": "$TEST_IMG"
+          "driver": "null-co"
       }
     }
   }
@@ -92,8 +91,7 @@ run_qemu -drive driver=$IMGFMT,id=disk,node-name=test-node,file="$TEST_IMG" <<EO
       "driver": "$IMGFMT",
       "node-name": "test-node",
       "file": {
-          "driver": "file",
-          "filename": "$TEST_IMG"
+          "driver": "null-co"
       }
     }
   }
-- 
2.9.3