getHostKey returns empty string, and patch determines that there are nulls there...

[mgajda]

I get the following result from getHostKey:
("", 42, ...)
This indicates that the string of length 42 is returned.
Such a string should be converted using CStringLen, not CString.
And indeed my patch fixes this:
mgajda@c966163

Please consider merging, if this is intended behaviour, but it seems to not work with checkKnownHosts, does it?