Fix: Invalid free on session_name when destroying session

Fix: Invalid free on session_name when destroying session

The session_name should not be free(3) if the user has specified a
session name on the command line. Also, the caller is responsible to
free the allocated string when calling get_session_name().  Handle both
cases gracefully.

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Christian Babeux <christian.babeux@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>