"charm create foo" error is weird if package doesn't exist

[Jorge Castro]

$ charm create foo
Generating template for foo from templates in /usr/share/charm-tools/templates
Charm will be stored in ./foo
failed to find foo in apt cache.

charm-tools creates foo but "failed to find foo in apt cache." makes me think that there was an error, perhaps we can just fix the wording:

$ charm create foo
Generating template for foo from templates in /usr/share/charm-tools/templates
Failed to find foo in apt cache, creating an empty charm instead
Charm will be stored in ./foo

would make that more clear.

[Nathan Osman (george-edison55)]

Confirmed: this happened to me as well.

[Marco Ceppi (marcoceppi)]

$ charm create foo
Generating template for foo from templates in /home/marco/Projects/charm-tools/templates
Charm will be stored in ./foo
Failed to find foo in apt cache, creating an empty charm instead.

I've pushed this change to the attached branch and opened a merge request.