Fix duplicate error message

[pd93]

Fixes #1141

I think this PR is a nice, clean solution to the problem. Unfortunately, as you can see, it also has the side-effect of removing the red coloured text from the error message since the executor/logger are out of scope in main 🙁 I'm not sure what the best solution is for this. We weren't always consistent with showing errors in coloured text anyway.

• We could potentially return the executor/logger back to the main function and use the logger that way. However, the logger isn't actually setup until we call e.Setup() and errors can occur before that which would result in nil pointer panics.
• We could just not use the logger at all and print a raw ANSI code to get the color, but we'd need to build in cases for the --color flag and NO_COLOR envvar.

@andreynering wdyt?

Also, since we needed access to the flags in the main function, I've moved them to a package-level struct variable. It means we can access them outside the run() function and also has the nice side-effect of namespacing the variables. i.e. versionFlag -> flag.version

[andreynering]

Hey @pd93, thanks for the fix.

Take a look at the commit. I just instantiated the logger.Logger struct manually and it was enough to make it work and still respect settings like --color=false, NO_COLOR=1, etc.