aria2::LpdMessageDispatcherTest: 2 tests fail without network access

[mgorny]

When running tests in a network namespace without Internet access, I get the following two failures:

##Failure Location unknown## : Error
Test name: aria2::LpdMessageDispatcherTest::testSendMessage
uncaught exception of type std::exception (or derived).
- Failed to set a socket option, cause: No such device

LpdMessageReceiverTest.cc:34:Assertion
Test name: aria2::LpdMessageReceiverTest::testReceiveMessage
assertion failed
- Expression: rcv.init("")

Failures !!!
Run: 979   Failure total: 2   Failures: 1   Errors: 1

I can reproduce it reliably with 1.35.0 and git master.

test-suite.log