[PATCH] iotests: fix _check_o_direct

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

Unfortunately commit "iotests: handle tmpfs" break running iotests
with -nbd -nocache, as _check_o_direct tries to create
$TEST_IMG.test_o_direct, but in case of nbd TEST_IMG is smothing like
nbd+unix:///... , and test fails with message

  qemu-img: nbd+unix:///?socket[...]test_o_direct: Protocol driver
    'nbd' does not support image creation, and opening the image
    failed: Failed to connect to '/tmp/tmp.[...]/nbd/test_o_direct': No
    such file or directory

Use TEST_DIR instead.

Fixes: cfdca2b9f9d4ca26bb2b2dfe8de3149092e39170
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 tests/qemu-iotests/common.rc | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 29354654cc..297acf9b6a 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -821,9 +821,10 @@ _supported_cache_modes()
 # Check whether the filesystem supports O_DIRECT
 _check_o_direct()
 {
-    $QEMU_IMG create -f raw "$TEST_IMG".test_o_direct 1M > /dev/null
-    out=$($QEMU_IO -f raw -t none -c quit "$TEST_IMG".test_o_direct 2>&1)
-    rm -f "$TEST_IMG".test_o_direct
+    testfile="$TEST_DIR"/_check_o_direct
+    $QEMU_IMG create -f raw "$testfile" 1M > /dev/null
+    out=$($QEMU_IO -f raw -t none -c quit "$testfile" 2>&1)
+    rm -f "$testfile"
 
     [[ "$out" != *"O_DIRECT"* ]]
 }
-- 
2.25.4