QNetworkSession::activeTime() returns constant 0 value for active connection

Test case:

• temporarily apply the attached patch to bearermonitor example
• start modified bearermonitor example on device
• click "open" on an connection that is valid and opened by Maemo, eg a WIFI access point
• observe in the console output from the modified bearermonitor example that value for activeTime() does not change from 0

Expected result: that QNetworkSession::activeTime() returns a value related to the length of time that the network session was open for.