test: fix race in ARP replies for SNAT external ips

There is a small race where gw-router-port can be running on both
hvs and both of them can reply to the arp request ending up with
two arp replies in the pcap file. This is transitory not significant
in a real deployment that can trigger a fail here. Let's use
greq -q instead.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Numan Siddique <numans@ovn.org>
(cherry picked from commit 906858c)

tests/ovn.at

@@ -25955,9 +25955,13 @@ test_arp_response () {
         test $($PYTHON "$ovs_srcdir/utilities/ovs-pcap.in" hv2/phys1-tx.pcap | wc -l) -ge 1
     ])
 
+    # there is a small race where gw-router-port can be running on both
+    # hvs and both of them can reply to the arp request ending up with
+    # two arp replies in the pcap file. This is transitory not significant
+    # in a real deployment that can trigger a fail here. Let's use
+    # greq -q instead.
     AT_CHECK([$PYTHON "$ovs_srcdir/utilities/ovs-pcap.in" hv2/phys1-tx.pcap | \
-    grep -c $arp_reply], [0], [1
-])
+    grep -q $arp_reply], [0])
 
     # $gw phys1-n1 should see the response because $gw ovn-controller responds
     # to arp request.
@@ -25995,7 +25999,7 @@ hv3_uuid=$(ovn-sbctl --bare --columns _uuid list chassis hv3)
 
 OVS_WAIT_UNTIL([
     cr_lr0_public_ch=$(ovn-sbctl --bare --columns chassis list port_binding cr-lr0-public)
-    test $cr_lr0_public_ch = $hv3_uuid
+    test "$cr_lr0_public_ch" = $hv3_uuid
 ])
 
 test_arp_response 000020201213 $(ip_to_hex 172 16 0 100) hv3 hv1 hv2
@@ -26008,7 +26012,7 @@ hv1_uuid=$(ovn-sbctl --bare --columns _uuid list chassis hv1)
 
 OVS_WAIT_UNTIL([
     gw_router_ch=$(ovn-sbctl --bare --columns chassis list port_binding gw_router-public)
-    test $gw_router_ch = $hv1_uuid
+    test "$gw_router_ch" = $hv1_uuid
 ])
 
 # Send ARP request for the IP which belongs to gw_router