scout-on-soldier: Fail if toolmanifest.vdf has not been reloaded
If the user was previously running a self-contained version of scout, toolmanifest.vdf will need to be reloaded before we will get run in a soldier container as required. Implement the entry point path used in the self-contained version as a script that just pops up a zenity error. (T28437)
Edited by Simon McVittie