Session is not invalidating after password change (Bug #1363873)

Scenario/testing:

- Create an account, say User A and logout as admin.
- In one browser login (this will be the hacker user)
- In another browser reset pass via forgotten pass link

What should happen:
User in browser two should be able to reset pass then navigate about
as when normally logged in. User in browser one should be forced to
login again as their user sessionid is not valid anymore.

Before patch:
malicious user still has access until $USER->logout_time time expires

After patch:
malicious user foreced to re-login straight away on next page load

Change-Id: I42ad907e5ffa7c128742a159116cf20dc6cd9b8a
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
Merge "Session is not invalidating after password change (Bug #1363873)" into 1.8_STABLE