#150 Strange SLPIfaceGetInfo() return value

[Hallvard B Furuseth]

SLPIfaceGetInfo() in openslp-2.0.0 can return
sts = (errno = EINVAL), -1; / not v4, not v6 /
That's the same as sts = errno = EINVAL; // ignore -1;
Maybe it intended to be sts = ((void)(errno = EINVAL), -1);

[John Calcote]

fixed.