netipmid: use std::shared_ptr instead of weak_ptr/lock

All of the instances of getSession and startSession were assigning the
result to a local shared_ptr via lock on the weak_ptr. It doesn't make
sense to demote the shared_ptr (from the sessionsMap) to a weak_ptr via
the return, only to promote to a shared_ptr again via lock.

Tested-by: running ipmitool -H a.b.c.d -P 0penBmc -I lanplus mc info
           Sessions start and stop, same as before.

Change-Id: Ic10779285891d73ee51115f16ed0000b38d1c52a
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
diff --git a/sessions_manager.cpp b/sessions_manager.cpp
index 10c2764..bf7ff34 100644
--- a/sessions_manager.cpp
+++ b/sessions_manager.cpp
@@ -24,7 +24,7 @@
     std::srand(std::time(0));
 }
 
-std::weak_ptr<Session>
+std::shared_ptr<Session>
     Manager::startSession(SessionID remoteConsoleSessID, Privilege priv,
                           cipher::rakp_auth::Algorithms authAlgo,
                           cipher::integrity::Algorithms intAlgo,
@@ -120,8 +120,8 @@
     }
 }
 
-std::weak_ptr<Session> Manager::getSession(SessionID sessionID,
-                                           RetrieveOption option)
+std::shared_ptr<Session> Manager::getSession(SessionID sessionID,
+                                             RetrieveOption option)
 {
     switch (option)
     {