test: ums: Add sleep before unmount directory

This change helps to run script on machines with quite long uptime.
Without this the following error emerges:

File: ./dat_14M.img
umount: /mnt/tmp-ums-test: device is busy.
        (In some cases useful info about processes that use
         the device is found by lsof(8) or fuser(1))
TX: md5sum:083d3d22b542d3ecba61b12d17e03f9f
mount: /dev/sdd6 already mounted or /mnt/tmp-ums-test busy
mount: according to mtab, /dev/sdd6 is already mounted on /mnt/tmp-ums-test

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
diff --git a/test/ums/ums_gadget_test.sh b/test/ums/ums_gadget_test.sh
index 56d4616..9da486b 100755
--- a/test/ums/ums_gadget_test.sh
+++ b/test/ums/ums_gadget_test.sh
@@ -11,6 +11,7 @@
 
 COLOUR_RED="\33[31m"
 COLOUR_GREEN="\33[32m"
+COLOUR_ORANGE="\33[33m"
 COLOUR_DEFAULT="\33[0m"
 
 DIR=./
@@ -59,8 +60,15 @@
     fi
 
     cp ./$1 $MNT_DIR
-    umount $MNT_DIR
 
+    while true; do
+	umount $MNT_DIR > /dev/null 2>&1
+	if [ $? -eq 0 ]; then
+	    break
+	fi
+	printf "$COLOUR_ORANGE\tSleeping to wait for umount...$COLOUR_DEFAULT\n"
+	sleep 1
+    done
 
     echo -n "TX: "
     calculate_md5sum $1