Scheduler::FillRecordingDir: Fix a race condition trying to start a

recording before being fulling initialized.

If a recording is 'in progress' when mythbackend starts up, it could fail to
record because the scheduler tries to start it up before it knows what
directory to store it in.

mythtv/programs/mythbackend/scheduler.cpp

@@ -5048,6 +5048,14 @@ int Scheduler::FillRecordingDir(
 {
     LOG(VB_SCHEDULE, LOG_INFO, LOC + "FillRecordingDir: Starting");
 
+    uint cnt = 0;
+    while (!m_mainServer)
+    {
+        if (cnt++ % 20 == 0)
+            LOG(VB_SCHEDULE, LOG_WARNING, "Waiting for main server.");
+        usleep(50000);
+    }
+
     int fsID = -1;
     MSqlQuery query(MSqlQuery::InitCon());
     QMap<QString, FileSystemInfo>::Iterator fsit;