[PATCH] selftests: net: tcp_fastopen_backup_key.sh: fix shellcheck issue

[Anders Roxell]

When running tcp_fastopen_backup_key.sh the following issue was seen in
a busybox environment.
./tcp_fastopen_backup_key.sh: line 33: [: -ne: unary operator expected

Shellcheck showed the following issue.
$ shellcheck tools/testing/selftests/net/tcp_fastopen_backup_key.sh

In tools/testing/selftests/net/tcp_fastopen_backup_key.sh line 33:
        if [ $val -ne 0 ]; then
             ^-- SC2086: Double quote to prevent globbing and word splitting.

Rework to add double quotes around the variable 'val' that shellcheck
recommends.

Signed-off-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
---
 tools/testing/selftests/net/tcp_fastopen_backup_key.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/tcp_fastopen_backup_key.sh b/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
index 41476399e184..ba5ec3eb314e 100755
--- a/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
+++ b/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
@@ -30,7 +30,7 @@ do_test() {
 	ip netns exec "${NETNS}" ./tcp_fastopen_backup_key "$1"
 	val=$(ip netns exec "${NETNS}" nstat -az | \
 		grep TcpExtTCPFastOpenPassiveFail | awk '{print $2}')
-	if [ $val -ne 0 ]; then
+	if [ "$val" -ne 0 ]; then
 		echo "FAIL: TcpExtTCPFastOpenPassiveFail non-zero"
 		return 1
 	fi
-- 
2.20.1