CHEF-2286: Fixed that svn command can be ran on specific language environment

* Use default LC_ALL enviornment variable if set
* Use locale attribute (added), prior to LC_ALL
CHEF-2286: Fixed bug of enviornment variable treatment

* Fixed bug crashing when LC_ALL is nil
* Added to check LANG variable.
    * Priority order is resource.locale, LANG, and LC_ALL
CHEF-2286: Fixed spec failure for ruby 1.8.7
CHEF-2286: Fixed ENV variable treatment to preserve original and back it after spec finished