dmsquash-live/dmsquash-live-root.sh: add parameter rd.live.squashimg

rd.live.squashimg names the squash image in the rd.live.dir
and defaults to squashfs.img

https://bugzilla.redhat.com/show_bug.cgi?id=789036
https://bugzilla.redhat.com/show_bug.cgi?id=782108

modules.d/90dmsquash-live/dmsquash-live-root.sh

@@ -19,6 +19,9 @@ livedev="$1"
 # specified as their own things
 live_dir=$(getarg rd.live.dir -d live_dir)
 [ -z "$live_dir" ] && live_dir="LiveOS"
+squash_image=$(getarg rd.live.squashimg)
+[ -z "squash_image" ] && squash_image="squashfs.img"
+
 getargbool 0 rd.live.ram -d -y live_ram && live_ram="yes"
 getargbool 0 rd.live.overlay.reset -d -y reset_overlay && reset_overlay="yes"
 getargbool 0 rd.live.overlay.readonly -d -y readonly_overlay && readonly_overlay="--readonly" || readonly_overlay=""
@@ -180,8 +183,8 @@ if [ -n "$FSIMG" ] ; then
 fi
 
 # we might have an embedded fs image on squashfs (compressed live)
-if [ -e /run/initramfs/live/${live_dir}/squashfs.img ]; then
-    SQUASHED="/run/initramfs/live/${live_dir}/squashfs.img"
+if [ -e /run/initramfs/live/${live_dir}/${squash_image} ]; then
+    SQUASHED="/run/initramfs/live/${live_dir}/${squash_image}"
 fi
 
 if [ -e "$SQUASHED" ] ; then