initfs: update: handle no images to update

Notify the user if image wildcard expansion fails instead of printing
message about failing to find partition to flash.

The update script errors with the message that it can't figure out what
partition to flash for /run/initramfs/image-* if there are no images
pending.

Signed-off-by: Milton Miller <miltonm@us.ibm.com>
diff --git a/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh b/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh
index 268c6ad..97d4402 100755
--- a/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh
+++ b/meta-phosphor/common/recipes-phosphor/obmc-phosphor-initfs/files/obmc-update.sh
@@ -102,6 +102,7 @@
 
 whitelist=/run/initramfs/whitelist
 image=/run/initramfs/image-
+imglist=
 
 while test "$1" != "${1#-}"
 do
@@ -187,7 +188,15 @@
 	fi
 fi
 
-for f in $image*
+imglist=$(echo $image*)
+if test "$imglist" = "$image*" -a ! -e "$imglist"
+then
+	# shell didn't expand the wildcard, so no files exist
+	echo "No images found to update."
+	imglist=
+fi
+
+for f in $imglist
 do
 	m=$(findmtd ${f#$image})
 	if test -z "$m"
@@ -212,7 +221,7 @@
 
 if test -n "$doflash"
 then
-	for f in $image*
+	for f in $imglist
 	do
 		if test ! -s $f
 		then