templates/index: load correct system.map file
templates/index: load correct system.map file

After d0325d7ac043 (part of #163), the job description template file
has the fixed name boot/system.map. It was <zapp-name>.json before.

The auto-generated JavaScript code still used the old variable name
and one could thus not execute anything with the web interface.

zerovm/zpm,zerovm/zerovm-cli,zerovm/zpm,zerovm/zerovm-cli,zerovm/zpm,zerovm/zerovm-cli,zerovm/zpm,zerovm/zpm,zerovm/zerovm-cli,zerovm/zerovm-cli,zerovm/zerovm-cli,zerovm/zpm