Call DeleteSecurityContext during Logoff

SMBLibrary/Server/SMBServer.SMB1.cs

@@ -130,6 +130,7 @@ namespace SMBLibrary.Server
                 }
                 else if (command is LogoffAndXRequest)
                 {
+                    m_securityProvider.DeleteSecurityContext(ref session.SecurityContext.AuthenticationContext);
                     state.RemoveSession(header.UID);
                     return new LogoffAndXResponse();
                 }

SMBLibrary/Server/SMBServer.SMB2.cs

@@ -129,6 +129,7 @@ namespace SMBLibrary.Server
                 }
                 else if (command is LogoffRequest)
                 {
+                    m_securityProvider.DeleteSecurityContext(ref session.SecurityContext.AuthenticationContext);
                     state.RemoveSession(command.Header.SessionID);
                     return new LogoffResponse();
                 }