tests/qtest/netdev-socket: Raise connection timeout to 60 seconds

tests/qtest/netdev-socket: Raise connection timeout to 60 seconds

The netdev-socket test intermittently fails on our s390x CI runner:

633/659 ERROR:../tests/qtest/netdev-socket.c:197:test_stream_unix:
assertion failed (resp == expect): ("st0: index=0,type=stream,connection error\r\n" == "st0: index=0,type=stream,unix:/tmp/netdev-socket.GZUG01/stream_unix\r\n")
ERROR
633/659 qemu:qtest+qtest-xtensa / qtest-xtensa/netdev-socket
ERROR           5.47s   killed by signal 6 SIGABRT

This may just be because when the machine is under heavy load
running the CI tests it hits the timeout before the QEMU
under test has started to the point of being able to respond
to HMP queries.

Bump the timeout to 60 seconds to see if the intermittent
goes away.

Acked-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20230207165119.1479132-1-peter.maydell@linaro.org