[buffermgr]: remove the item from consumer queue if invalid (sonic-net#489)

* [buffermgr]: remove the item from consumer queue if invalid

Signed-off-by: Sihui Han <sihan@microsoft.com>

* change error to task_invalid_entry

Signed-off-by: Sihui Han <sihan@microsoft.com>

Author: sihuihan88

cfgmgr/buffermgr.cpp

@@ -126,7 +126,7 @@ task_process_status BufferMgr::doSpeedUpdateTask(string port, string speed)
     {
         SWSS_LOG_ERROR("Unable to create/update PG profile for port %s. No PG profile configured for speed %s and cable length %s",
                        port.c_str(), speed.c_str(), cable.c_str());
-        return task_process_status::task_failed;
+        return task_process_status::task_invalid_entry;
     }
 
     // Crete record in BUFFER_PROFILE table
@@ -222,6 +222,10 @@ void BufferMgr::doTask(Consumer &consumer)
                 SWSS_LOG_INFO("Unable to process table update. Will retry...");
                 ++it;
                 break;
+            case task_process_status::task_invalid_entry:
+                SWSS_LOG_ERROR("Failed to process invalid entry, drop it");
+                it = consumer.m_toSync.erase(it);
+                break;
             default:
                 it = consumer.m_toSync.erase(it);
                 break;