Revert "Use real Neutron network for L3 GW by default"

This reverts commit 130a11f8aaf08ea529b6ce60dd9052451cb7bb5c.
Linux bridge devstack logic needs some changes first.

Change-Id: I5885062ad128518c22f743db016e1a6db64f3313
Closes-Bug: #1605423
diff --git a/lib/neutron_plugins/services/l3 b/lib/neutron_plugins/services/l3
index 816679e..2180099 100644
--- a/lib/neutron_plugins/services/l3
+++ b/lib/neutron_plugins/services/l3
@@ -17,11 +17,6 @@
 PUBLIC_BRIDGE=${PUBLIC_BRIDGE:-br-ex}
 PUBLIC_BRIDGE_MTU=${PUBLIC_BRIDGE_MTU:-1500}
 
-# If Q_ASSIGN_GATEWAY_TO_PUBLIC_BRIDGE=True, assign the gateway IP of the public
-# subnet to the public bridge interface even if Q_USE_PROVIDERNET_FOR_PUBLIC is
-# used.
-Q_ASSIGN_GATEWAY_TO_PUBLIC_BRIDGE=${Q_ASSIGN_GATEWAY_TO_PUBLIC_BRIDGE:-True}
-
 # If Q_USE_PUBLIC_VETH=True, create and use a veth pair instead of
 # PUBLIC_BRIDGE.  This is intended to be used with
 # Q_USE_PROVIDERNET_FOR_PUBLIC=True.
@@ -56,7 +51,7 @@
 #    Q_USE_PROVIDERNET_FOR_PUBLIC=True
 #    PUBLIC_PHYSICAL_NETWORK=public
 #    OVS_BRIDGE_MAPPINGS=public:br-ex
-Q_USE_PROVIDERNET_FOR_PUBLIC=${Q_USE_PROVIDERNET_FOR_PUBLIC:-True}
+Q_USE_PROVIDERNET_FOR_PUBLIC=${Q_USE_PROVIDERNET_FOR_PUBLIC:-False}
 PUBLIC_PHYSICAL_NETWORK=${PUBLIC_PHYSICAL_NETWORK:-public}
 
 # Generate 40-bit IPv6 Global ID to comply with RFC 4193
@@ -310,7 +305,7 @@
             local cidr_len=${FLOATING_RANGE#*/}
             local testcmd="ip -o link | grep -q $ext_gw_interface"
             test_with_retry "$testcmd" "$ext_gw_interface creation failed"
-            if [[ $(ip addr show dev $ext_gw_interface | grep -c $ext_gw_ip) == 0 && ( $Q_USE_PROVIDERNET_FOR_PUBLIC == "False" || $Q_USE_PUBLIC_VETH == "True" || $Q_ASSIGN_GATEWAY_TO_PUBLIC_BRIDGE == "True" ) ]]; then
+            if [[ $(ip addr show dev $ext_gw_interface | grep -c $ext_gw_ip) == 0 && ( $Q_USE_PROVIDERNET_FOR_PUBLIC == "False" || $Q_USE_PUBLIC_VETH == "True" ) ]]; then
                 sudo ip addr add $ext_gw_ip/$cidr_len dev $ext_gw_interface
                 sudo ip link set $ext_gw_interface up
             fi