Fixes OS detection on mdraid devices

Bug: https://bugs.debian.org/648251
     https://bugzilla.redhat.com/752402

--- a/os-prober
+++ b/os-prober
@@ -64,6 +64,11 @@ partitions () {
 		exit 0
 	fi
 
+	# Add MD RAID devices
+	if [ -f /proc/mdstat ] ; then
+		awk '/^md/ {printf "/dev/"$1"\n"}' /proc/mdstat
+	fi
+
 	# Also detect OSes on LVM volumes (assumes LVM is active)
 	if type lvs >/dev/null 2>&1; then
 		echo "$(LVM_SUPPRESS_FD_WARNINGS=1 log_output lvs --noheadings --separator : -o vg_name,lv_name |
@@ -123,7 +128,7 @@ if [ -f /proc/swaps ]; then
 fi
 : >"$OS_PROBER_TMP/raided-map"
 if [ -f /proc/mdstat ] ; then
-	grep "^md" /proc/mdstat | parse_proc_mdstat >"$OS_PROBER_TMP/raided-map" || true
+	grep "^md" /proc/mdstat | cut -d: -f2- | parse_proc_mdstat >"$OS_PROBER_TMP/raided-map" || true
 fi
 
 for partition in $(partitions); do