MFH: r432967

multimedia/vdr: unbreak with clang 4.0

recording.c:2090:17: error: ordered comparison between pointer and zero ('cUnbufferedFile *' and 'int')

if (Open() >= 0) {
    ~~~~~~ ^  ~

PR: 216058
Reported by: antoine (via exp-run)
Approved by: ports-secteam blanket