Fix for newer version of ruby

to_s converts Array with backquotes in latests versions of ruby
```bash
$ ruby -v           
ruby 1.8.7 (2011-06-30 patchlevel 352) [x86_64-linux]
$ irb
irb(main):001:0> ["sda"].to_s
=> "sda"
irb(main):002:0> ["sda"].first.to_s
=> "sda"



$ ruby -v
ruby 1.9.3p392 (2013-02-22 revision 39386) [x86_64-linux]
$ irb
irb(main):001:0> ["sda"].to_s
=> "[\"sda\"]"
irb(main):001:0> ["sda"].first.to_s
=> "sda"
```