Silence the NULL hostname error in jobqueue

Make it initialize the jobHost to QString("") now that we are being more
careful about passing NULL.  When we want to send jobs to any host, "" should
work.

mythtv/libs/libmythtv/jobqueue.cpp

@@ -489,7 +489,7 @@ bool JobQueue::QueueRecordingJobs(const RecordingInfo &recinfo, int jobTypes)
 
     if (jobTypes != JOB_NONE)
     {
-        QString jobHost;
+        QString jobHost = QString("");
 
         if (gCoreContext->GetNumSetting("JobsRunOnRecordHost", 0))
             jobHost = recinfo.GetHostname();