Handle Bundler::GemfileNotFound

[werthen]

Summary

In #910, some interaction with Bundler was introduced. However, when running nanoc from commandline immediately, without a Gemfile or .bundle directory being present (when creating a new site, for example), a script created by rubygems gets called, which includes Bundler. This would give the following error any time nanoc gets called from CLI

☁  Projects  nanoc create-site cv

Captain! We’ve been hit!

Message:

Bundler::GemfileNotFound: Could not locate Gemfile or .bundle/ directory

Detailed description

We add a rescue block in order to prevent nanoc from crashing. If there's no Gemfile, nothing should happen anyway.

Crashlog

https://gist.github.com/werthen/ffa7610068ea5afa956fe5f12c8d20ea

[denisdefreyne]

I have not been able to come up with a reproduction scenario for this bug, but as it seems like a plausible situation, I’ve decided to merge it anyway.