It's used to indicate the special case where a valid file-descriptor
is returned (ie. success) but the connection can't be completed
w/o blocking.
This is needed because QERR_SOCKET_CONNECT_IN_PROGRESS is not
treated like an error and a future commit will drop it.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
