[archiso] Allow set copytoram=n for NBD/NFS

On low memory systems installing via PXE is not possible.
Do not force copytoram=y for NFS/NDB.
Broken/hang things:
* On shutdown.
* On run-time if some network settings changed.

Implements FS#32006.

Signed-off-by: Gerardo Exequiel Pozzi <vmlinuz386@yahoo.com.ar>

archiso/initcpio/hooks/archiso_pxe_nbd

@@ -27,7 +27,10 @@ archiso_pxe_nbd_mount_handler () {
     msg ":: Setup NBD from ${archiso_nbd_srv} at /dev/nbd0"
     nbd-client ${archiso_nbd_srv} -N ${archiso_nbd_name} /dev/nbd0
 
-    copytoram="y"
+    if [[ "${copytoram}" != "n" ]]; then
+        copytoram="y"
+    fi
+
     archisodevice=/dev/nbd0
 
     archiso_mount_handler ${newroot}

archiso/initcpio/hooks/archiso_pxe_nfs

@@ -22,6 +22,9 @@ archiso_nfs_mount_handler() {
         launch_interactive_shell
     fi
 
-    copytoram="y"
+    if [[ "${copytoram}" != "n" ]]; then
+        copytoram="y"
+    fi
+
     archiso_mount_handler ${newroot}
 }