golden: blackhawk: Fix bootmenu.sh

We need to bind mount
"/.secondrom/media" and
"/.secondrom/media/.secondrom/data /data" before replaceing
original mount and umount scripts for second recovery.
This will fix failing backup for 2nd Rom in recovery.

Change-Id: I37993f8af40733b8ce2786858e252afb3f0ae9aa