Fix MBR/msdosfs partition unmount issue.

automount

@@ -144,7 +144,7 @@ EOF
 
 if [ "${1}" = "--version" -o "${1}" = "-version" -o "${1}" = "version" ]
 then
-  echo "automount 1.6.0 2018/12/10"
+  echo "automount 1.6.1 2019/01/11"
   exit 0
 fi
 
@@ -720,6 +720,7 @@ case ${1} in
                 unset TARGET
                 __log "${DEV}: umount"
               done
+          umount -f "${MNTPREFIX}/${1}"
           __remove_dir "${MNTPREFIX}/${1}"
           __log "${DEV}: mount point '${MNTPREFIX}/${1}' removed"
         fi