vhost: fix error code check when creating thread
vhost: fix error code check when creating thread

On error, pthread_create() returns a positive number (errno).
Fix the test on the return value.

Fixes: af1475918124 ("vhost: introduce API to start a specific driver")
Fixes: e623e0c6d8a5 ("vhost: add reconnect ability")
Cc: stable@dpdk.org

Signed-off-by: Olivier Matz <dfcc1510895413197abb4336e39bb0a3906cba71@6wind.com>
Reviewed-by: Maxime Coquelin <9a2667dee3b90866bbc9c2696cff2b7d5616c95a@redhat.com>
Reviewed-by: Jens Freimann <ca9361fbe2c56b38bfc6f0fa839493a196cfbd8f@redhat.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk