Bump up intra-cluster import connect timeout

Currently, the export timeout is 10 times 20 seconds, but the import
is only 30 seconds. I'm raising this to 60 seconds with two goals in
mind:

- when debugging manually, this allows for easier synchronisation of
  the processes
- 60 equals to 3 full 20 second intervals, which I think is better
  than just one an a half

This change shouldn't make a big difference either way (at most, it
will possibly delay the job in case of failures by half a minute).

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>