Cherry pick gNMI and Stratum related changes to this branch

Cherry picked commits:
20211 Update gNMI version and build script
20247 [ONOS-7829] Implement AbstractGrpcClient and AbstractGrpcClientControl
20233 [ONOS-7141][ONOS-7142] Add GnmiClient and GnmiController
20234 Refactor OpenConfig gNMI device description descovery
20260 [ONOS-7831] Implement GnmiHandshaker
20270 Add Stratum driver

Change-Id: I81ad8bce45251af5909cfcac0edbcfd11c8ebf1d
diff --git a/drivers/gnmi/src/main/resources/gnmi-drivers.xml b/drivers/gnmi/src/main/resources/gnmi-drivers.xml
index 3744781..70c0b20 100644
--- a/drivers/gnmi/src/main/resources/gnmi-drivers.xml
+++ b/drivers/gnmi/src/main/resources/gnmi-drivers.xml
@@ -17,7 +17,9 @@
 <drivers>
     <driver name="gnmi" manufacturer="gnmi" hwVersion="master" swVersion="master">
         <behaviour api="org.onosproject.net.device.DeviceDescriptionDiscovery"
-                   impl="org.onosproject.drivers.gnmi.GnmiDeviceDescriptionDiscovery"/>
+                   impl="org.onosproject.drivers.gnmi.OpenConfigGnmiDeviceDescriptionDiscovery"/>
+        <behaviour api="org.onosproject.net.device.DeviceHandshaker"
+                   impl="org.onosproject.drivers.gnmi.GnmiHandshaker"/>
     </driver>
 </drivers>