contrail-collector crash immediately after provisioning

root cause:
  To state_machine_, sandesh_connection is owner as scoped_ptr.
  generator as user use state_machine_.get() to access. sandesh
  _connection will deal with connection close message in one core
  but generator will deal with redis message in another core. This
  lead source race condition. We have use mutex lock to protect.
  but mutex is one part of state_machine_ structure, so to
  destructed fucntion of state_machine_, protecting is invalid.
Solution:
  Change scoped_ptr to shared_ptr.

Change-Id: I1756f8dc0cdd1e7b705af9f1650c6bb8b118e212
Partial-Bug: 1755649

library/cpp/sandesh_connection.cc

@@ -99,6 +99,11 @@ SandeshStateMachine *SandeshConnection::state_machine() const {
     return state_machine_.get();
 }
 
+boost::shared_ptr<SandeshStateMachine>
+SandeshConnection::shared_state_machine() const {
+    return state_machine_;
+}
+
 void SandeshConnection::SetAdminState(bool down) {
     if (admin_down_ != down) {
         admin_down_ = down;

library/cpp/sandesh_connection.h

@@ -45,6 +45,7 @@ class SandeshConnection {
 
     SandeshSession *session() const;
     SandeshStateMachine *state_machine() const;
+    boost::shared_ptr<SandeshStateMachine> shared_state_machine() const;
 
     std::string StateName() const { return state_machine_->StateName(); }
 
@@ -91,8 +92,8 @@ class SandeshConnection {
     SandeshSession *session_;
     int task_instance_;
     int task_id_;
-    boost::scoped_ptr<SandeshStateMachine> state_machine_;
-    
+    boost::shared_ptr<SandeshStateMachine> state_machine_;
+
     DISALLOW_COPY_AND_ASSIGN(SandeshConnection);
 };