fstab: make requied changes so that the /etc overlay get mounted eari…

…er in the boot process

Having "noauto" among flags postpone the overlay mount to a moment where services are started already, making it impossible to disable/enable services.

Fix the above issue (and very probably more) by having the overlay mounted earlier in the boot sequence.

/sysroot is the directory systemd (in initramfs) mounts the new rootfs to (before performing the switch_root syscall to it) and raw fs arguments (unparsed by systemd) needs to specify that directory.

build-image.sh

@@ -151,10 +151,10 @@ Subsystem	sftp	/usr/lib/ssh/sftp-server
 " > /etc/ssh/sshd_config
 
 echo "
-LABEL=frzr_root /var       btrfs     defaults,subvolid=256,rw,noatime,nodatacow,nofail                                                                                  0   0
-LABEL=frzr_root /home      btrfs     defaults,subvolid=257,rw,noatime,nodatacow,nofail                                                                                  0   0
-LABEL=frzr_root /frzr_root btrfs     defaults,subvolid=5,rw,noatime,nodatacow,x-initrd                                                                                  0   2
-overlay       /etc       overlay noauto,x-systemd.requires=/frzr_root,x-systemd.rw-only,lowerdir=/etc,upperdir=/frzr_root/etc,workdir=/frzr_root/.etc,index=off,metacopy=off,comment=etcoverlay    0   0
+LABEL=frzr_root /var       btrfs     defaults,subvolid=256,rw,noatime,nodatacow,nofail                                                                                                                                           0   0
+LABEL=frzr_root /home      btrfs     defaults,subvolid=257,rw,noatime,nodatacow,nofail                                                                                                                                           0   0
+LABEL=frzr_root /frzr_root btrfs     defaults,subvolid=5,rw,noatime,nodatacow,x-initrd                                                                                                                                           0   2
+overlay         /etc       overlay   defaults,x-systemd.requires=/frzr_root,x-systemd.rw-only,lowerdir=/sysroot/etc,upperdir=/sysroot/frzr_root/etc,workdir=/sysroot/frzr_root/.etc,index=off,metacopy=off,comment=etcoverlay    0   0
 " > /etc/fstab
 
 echo "