support/testing: test_oci: update to _OCI_CMD option

BR2_TARGET_ROOTFS_OCI_ENTRYPOINT_ARGS option has been
replaced by BR2_TARGET_ROOTFS_OCI_CMD in commit [1].

Since BR2_TARGET_ROOTFS_OCI_ENTRYPOINT_ARGS contains
only one item, we can safely replace by
BR2_TARGET_ROOTFS_OCI_CMD in the defconfig fragment
used by the test_oci test case.

Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/2491321058

[1] 08d65d81d88418b0cd7edd3bd2227faa58d022f0

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Yann E. MORIN <yann.morin@orange.com>
Cc: Sergio Prado <sergio.prado@e-labworks.com>
Cc: Matthew Weber <matthew.weber@collins.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

support/testing/tests/fs/test_oci.py

@@ -20,7 +20,7 @@ class TestOci(infra.basetest.BRTest):
         BR2_TARGET_ROOTFS_EXT2_SIZE="600M"
         BR2_TARGET_ROOTFS_OCI=y
         BR2_TARGET_ROOTFS_OCI_ENTRYPOINT="df"
-        BR2_TARGET_ROOTFS_OCI_ENTRYPOINT_ARGS="-h"
+        BR2_TARGET_ROOTFS_OCI_CMD="-h"
         BR2_TARGET_ROOTFS_OCI_ARCHIVE=y
         # BR2_TARGET_ROOTFS_TAR is not set
         """