Increase the count of ping probes

It's allowed now to get at least 3 answers for no more than 10 requests.
Interval between connectivity checks is increaced (30 -> 60 sec).

Closes-Bug: #1322102
Change-Id: Iec2b68d2e8f93cf57e1db93953c79d20d3fb86c7
Original Change-Id: I0b227e3426c3d8b453986e6545829a11e125ce0b