increase 1-second timeout in fetchlimit

when "checking lame server clients are dropped below the hard limit", periodically a query is sent for a name for which the server is authoritative, to verify that legitimate queries can still be processed while the server is dealing with a flood of lame delegation queries. those queries used the same dig options as elsewhere in the fetchlimit test, including "+tries=1 +timeout=1". on slow systems, a 1-second timeout may be insufficient to get an answer even if the server is behaving well. this commit increases the timeout for the check queries to 2 seconds in hopes that will be enough to eliminate test failures in CI.

Closes #69 (closed)