iotests: remove remaining calls to qemu_img_pipe()

iotests: remove remaining calls to qemu_img_pipe()

As part of moving all python iotest invocations of qemu-img onto a
single qemu_img() implementation, remove a few lingering uses of
qemu_img_pipe() from outside of iotests.py itself.

Several cases here rely on the knowledge that qemu_img_pipe() suppresses
*all* output on a successful case when the command being issued is
'create'.

065: This call's output is inspected, but it appears as if it's expected
     to succeed. Replace this call with the checked qemu_img() variant
     instead to get better diagnostics if/when qemu-img itself fails.

237: "create" call output isn't actually logged. Use qemu_img_create()
     instead, which checks the return code. Remove the empty lines from
     the test output.

296: Two calls;
     -create: Expected to succeed. Like other create calls, the output
              isn't actually logged.  Switch to a checked variant
              (qemu_img_create) instead. The output for this test is
              a mixture of both test styles, so actually replace the
              blank line for readability.
     -amend:  This is expected to fail. Log the output.

After this patch, the only uses of qemu_img_pipe are internal to
iotests.py and will be removed in subsequent patches.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220321201618.903471-15-jsnow@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>