Remove _get_compute_info from filter_scheduler.py

After patch I6de33ada6dc377e20f8df07da92244f2c150b9fe and
Ie6f104368140b69a60e124ea96ef6bf7715fe34e, in filter_scheduler.py,
_get_compute_info has no use and no one is calling it, so we
can remove it directly.

Fix bug 1228475

Change-Id: Ia85068e402b6f0b2a9ed2a809d1c1dc63e0f3041

nova/scheduler/filter_scheduler.py

@@ -24,7 +24,6 @@ import random
 from oslo.config import cfg
 
 from nova.compute import rpcapi as compute_rpcapi
-from nova import db
 from nova import exception
 from nova import notifier
 from nova.openstack.common.gettextutils import _
@@ -360,14 +359,3 @@ class FilterScheduler(driver.Scheduler):
             if update_group_hosts is True:
                 filter_properties['group_hosts'].append(chosen_host.obj.host)
         return selected_hosts
-
-    def _get_compute_info(self, context, dest):
-        """Get compute node's information
-
-        :param context: security context
-        :param dest: hostname (must be compute node)
-        :return: dict of compute node information
-
-        """
-        service_ref = db.service_get_by_compute_host(context, dest)
-        return service_ref['compute_node'][0]