Explicitly sets dumpsys timeout.

The run_command() function takes a timeout as argument, and dumpsys can
also optionally takes a timeout with the -t argument, hence it makes
sense to pass the same value for both (otherwise dumpsys will timeout in
10s).

BUG: 29042642
Change-Id: Ib6e987d94e966686bab71223d7f910af9e549814