Do not keep trying to mount when it fails

Refs #10221

If a USB stick (or other removable drive) is attached to the frontend, and the
user running the frontend is not able to mount it with "mount /dev/sdc1" or the
like, we do not want to keep trying (twice a second!) to mount it.  There's
no purpose to that other than extra load, and filling log files with useless
crap.

mythtv/libs/libmythbase/mythhdd.cpp

@@ -33,15 +33,19 @@ MythHDD::MythHDD(QObject *par, const char *DevicePath,
  */
 MythMediaStatus MythHDD::checkMedia(void)
 {
+    if (m_Status == MEDIASTAT_ERROR)
+        return m_Status;
+
     if (isMounted())
     {
         // A lazy way to present volume name for the user to eject.
         // Hotplug devices are usually something like /media/VOLUME
         m_VolumeID = m_MountPath;
 
         // device is mounted, trigger event
-        if (MEDIASTAT_MOUNTED != m_Status)
+        if (m_Status != MEDIASTAT_MOUNTED)
             m_Status = MEDIASTAT_NOTMOUNTED;
+
         return setStatus(MEDIASTAT_MOUNTED);
     }
 
@@ -51,15 +55,16 @@ MythMediaStatus MythHDD::checkMedia(void)
     case MEDIASTAT_NOTMOUNTED:
         // a removable device was just plugged in try to mount it.
         LOG(VB_MEDIA, LOG_INFO, "MythHDD::checkMedia try mounting " + m_DevicePath);
+
         if (mount())
-        {
-            m_Status = MEDIASTAT_NOTMOUNTED;
             return setStatus(MEDIASTAT_MOUNTED);
-        }
-        return m_Status;
+
+        return setStatus(MEDIASTAT_ERROR);
+
     case MEDIASTAT_MOUNTED:
         // device was mounted and someone unmounted it.
-        return m_Status = setStatus(MEDIASTAT_NOTMOUNTED);
+        return setStatus(MEDIASTAT_NOTMOUNTED);
+
     default:
         // leave device state as is
         return m_Status;