Fix an OOB memory read in kio_sftp

When passing timeout values to ssh_option_set of security/libssh, an int type
pointer is used instead of a long int one required by the ssh_option_set
documentation, which causes platform specific (or undefined) behaviour on
architectures where sizeof (long int) is different to sizeof (int).

Fix this by "promoting" the referenced locals to long integer type.

This commit merges r10452 of area51 and is based on a report by Dwayne
MacKinnon via kde@ mailing list.

References:

https://mail.kde.org/pipermail/kde-freebsd/2014-October/018330.html
https://bugs.kde.org/show_bug.cgi?id=331674

Approved by: rakuco (mentor)