Replaced eval with const_get method

[szemek]

Hello @matschaffer
when I was running knife-solo on one of servers I received following error:

Bootstrapping Chef...
ERROR: SyntaxError: (eval):1: syntax error, unexpected ':', expecting end-of-input
...Solo::Bootstraps::bash:warning:setlocale:LC_ALL:cannotchange...
...                               ^

I started debugging and found interesting place. In my opinion eval is not necessary and const_get is sufficient, and what's more, const_get helps to spot an issue way faster.

Bootstrapping Chef...
ERROR: KnifeSolo::Bootstraps::OperatingSystemNotImplementedError: "bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)\r\nLinux" not implemented.  Feel free to add a bootstrap implementation in KnifeSolo::Bootstraps::bash:warning:setlocale:LC_ALL:cannotchangelocale(en_US.UTF-8)Linux

Happy New Year 🎉
@szemek

[matschaffer]

Thanks! You win first-merge of 2016 prize (at least from my time zone anyway)