selftests/net: correct the return value for run_netsocktests

BugLink: https://bugs.launchpad.net/bugs/1825777

The run_netsocktests will be marked as passed regardless the actual test
result from the ./socket:

    selftests: net: run_netsocktests
    ========================================
    --------------------
    running socket test
    --------------------
    [FAIL]
    ok 1..6 selftests: net: run_netsocktests [PASS]

This is because the test script itself has been successfully executed.
Fix this by exit 1 when the test failed.
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 30c04d79)
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Acked-by: Khalid Elmously <khalid.elmously@canonical.com>
Acked-by: Kleber Souza <kleber.souza@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

tools/testing/selftests/net/run_netsocktests

@@ -6,7 +6,7 @@ echo "--------------------"
 ./socket
 if [ $? -ne 0 ]; then
 	echo "[FAIL]"
+	exit 1
 else
 	echo "[PASS]"
 fi
-