Able to change lb algorithm on pool updating

Change-Id: I0470a02657f594b21826a34e2a24e7dbcdd87bcd
Story: 1713863
Task: 5370

octavia_dashboard/api/rest/lbaasv2.py

@@ -334,6 +334,7 @@ def update_pool(request, **kwargs):
     conn = _get_sdk_connection(request)
     pool = conn.load_balancer.update_pool(
         pool=pool_id,
+        lb_algorithm=data['pool']['method'],
         name=data['pool'].get('name'),
         description=data['pool'].get('description'))
 

octavia_dashboard/static/dashboard/project/lbaasv2/workflow/pool/pool.html

@@ -32,7 +32,7 @@
         <select class="form-control" name="method" id="method"
                 ng-options="method for method in model.methods"
                 ng-model="model.spec.pool.method"
-                ng-disabled="model.context.id" ng-required="true">
+                ng-required="true">
         </select>
       </div>
     </div>