ovs-vtep: Delete flows with untagged vlan carefully.

A (physical port + vlan) or (physical port + no tag) can be bound to a
logical switch. When one unbinds (physical port + no tag) from a logical
switch, the emulator inadvertantly deletes flows for (physical port + vlan)
too. This commit fixes it.

VMware-BZ: #1609938
Reported-by: Mike Qing <mqing@vmware.com>
Signed-off-by: Gurucharan Shetty <guru@ovn.org>
Acked-by: Ryan Moats <rmoats@us.ibm.com>

AUTHORS

@@ -357,6 +357,7 @@ Michael Shigorin        mike@osdn.org.ua
 Mihir Gangar            gangarm@vmware.com
 Mike Bursell            mike.bursell@citrix.com
 Mike Kruze              mkruze@nicira.com
+Mike Qing               mqing@vmware.com
 Min Chen                ustcer.tonychan@gmail.com
 Mikael Doverhag         mdoverhag@nicira.com
 Mrinmoy Das             mrdas@ixiacom.com

vtep/ovs-vtep

@@ -545,8 +545,8 @@ def del_binding(binding, ls):
                   % (ps_name, port_no, vlan_))
         ovs_ofctl("del-flows %s in_port=%s" % (ps_name, patch_no))
     else:
-        ovs_ofctl("del-flows %s in_port=%s" % (ps_name, port_no))
-        ovs_ofctl("del-flows %s in_port=%s" % (ps_name, patch_no))
+        ovs_ofctl("--strict del-flows %s in_port=%s" % (ps_name, port_no))
+        ovs_ofctl("--strict del-flows %s in_port=%s" % (ps_name, patch_no))
 
     ls.del_lbinding(lbinding)