Similar to other recent changes: use the qemu_img invocation that
supports throwing loud, nasty exceptions when it fails for surprising
reasons.

(Why would "--help" ever fail? I don't know, but consistency is like a
well-manicured bonsai.)

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/qemu-iotests/iotests.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index cbb3af71523..882d3e0214a 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -1428,8 +1428,8 @@ def _verify_imgopts(unsupported: Sequence[str] = ()) -> None:
         notrun(f'not suitable for this imgopts: {imgopts}')
 
 
-def supports_quorum():
-    return 'quorum' in qemu_img_pipe('--help')
+def supports_quorum() -> bool:
+    return 'quorum' in qemu_img('--help').stdout
 
 def verify_quorum():
     '''Skip test suite if quorum support is not available'''
-- 
2.34.1