[team sync/mgr] Add debug message before cleaning up LAGs (sonic-net#1192)

These functions are called only once in the time of service stopping,
add events will help debug. And these messages won't be chatty.

Signed-off-by: Ying Xie <ying.xie@microsoft.com>

Author: yxieca

cfgmgr/teammgr.cpp

@@ -163,6 +163,8 @@ void TeamMgr::cleanTeamProcesses(int signo)
 {
     pid_t pid = 0;
 
+    SWSS_LOG_ENTER();
+    SWSS_LOG_NOTICE("Cleaning up LAGs during shutdown...");
     for (const auto& it: m_lagList)
     {
         pid = m_lagPIDList[it];

teamsyncd/teamsync.cpp

@@ -212,6 +212,9 @@ void TeamSync::removeLag(const string &lagName)
 
 void TeamSync::cleanTeamSync()
 {
+    SWSS_LOG_ENTER();
+    SWSS_LOG_NOTICE("Cleaning up LAG teamd resources ...");
+
     for (const auto& it: m_teamSelectables)
     {
         /* Cleanup LAG */