selftests: net: return non-zero for failures reported in arp_ndisc_evict_nocarrier

Return non-zero return value if there is any failure reported in this
script during the test. Otherwise it can only reflect the status of
the last command.

Fixes: f86ca07eb531 ("selftests: net: add arp_ndisc_evict_nocarrier")
Signed-off-by: Po-Hsu Lin <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

tools/testing/selftests/net/arp_ndisc_evict_nocarrier.sh

···
 readonly V6_ADDR0=2001:db8:91::1
 readonly V6_ADDR1=2001:db8:91::2
 nsid=100
+ret=0
 
 cleanup_v6()
 {
···
     if [ $? -ne 0 ]; then
         cleanup_v6
         echo "failed"
-        exit
+        exit 1
     fi
 
     # Set veth2 down, which will put veth1 in NOCARRIER state
···
     if [ $? -ne 0 ]; then
         cleanup_v4
         echo "failed"
-        exit
+        exit 1
     fi
 
     # Set veth1 down, which will put veth0 in NOCARRIER state
···
 
     if [ $? -eq 0 ];then
         echo "failed"
+        ret=1
     else
         echo "ok"
     fi
···
         echo "ok"
     else
         echo "failed"
+        ret=1
     fi
 
     cleanup_v4
···
 
     if [ $? -eq 0 ];then
         echo "failed"
+        ret=1
     else
         echo "ok"
     fi
···
         echo "ok"
     else
         echo "failed"
+        ret=1
     fi
 
     cleanup_v6
···
         echo "ok"
     else
         echo "failed"
+        ret=1
     fi
 
     cleanup_v6
···
 fi
 
 run_all_tests
+exit $ret