test/integration: Silence warning about which

Shellcheck complains with the following warning:
SC2230: which is non-standard.

It is probably fair to assume that which is available for now, so just
ignore the warning.

Signed-off-by: Julien Thierry <jthierry@redhat.com>

test/integration/lib.sh

@@ -229,6 +229,7 @@ kpatch_install_vagrant()
 kpatch_check_install_vagrant()
 {
 	local image_path=${1}
+	# shellcheck disable=SC2230
 	[ "$(which vagrant)" == "" ] && kpatch_install_vagrant "${image_path}"
 	return 0
 }