ikev2: cleanup stuck sessions

ikev2: cleanup stuck sessions

The following issues are fixed:
* in responder code: do lookup again as the old pointer could be
  invalidated during the cleanup operation
* in initiar code: do the cleanup of session if there're no child SAs or
  if there's no response from the responder during initial request (this
  can easily happen if the response packet was lost/dropped/etc)
* print the state of ikev2 profile (for easier tshooting)

Type: fix

Change-Id: I853d9851c0cf131696585e3c98fa97e66789badd
Signed-off-by: Stanislav Zaikin <stanislav.zaikin@46labs.com>