CHEF-2739 - Adds script_path feature

[kcbraunschweig]

This adds a key called script_path in the chef config that takes an array of paths to look for knife exec scripts. It defaults to an empty array to mimic existing behavior. If you set a path in your knife.rb, it'll be searched in cases where the specified script isn't found in the current directory. Has debug logging and adds a bit of error handling.

Backreference to ticket:

http://tickets.opscode.com/browse/CHEF-2739

[jaymzh]

You'll return here even if the script doesn't exist... shouldn't we throw an error? Or check it above?

[kcbraunschweig]

You're right, this error isn't handled explicitly. I didn't add anything to do this, but you get the same error as you do now. It looks like this:

kc@myhost:~$ knife exec foo
ERROR: Errno::ENOENT: No such file or directory - /home/kc/foo

For an unhandled error, its pretty clear, but I can look at what some other subcommands do and add something similar.

[jaymzh]

Good point...

[kcbraunschweig]

Commit below addresses this.

[kcbraunschweig]

One more commit to cleanup the flow. Thanks for your input.

[btm]

Merged to master. KC, be careful when merging onto topic branches (rebase instead) because even when the code appears right the commit history becomes broken. The above commits are a sign that this happened.

I cherry-picked your commits to avoid bringing this into the project commit history.

Thanks for the patch!