Handle tab-separated values better

[anders-larsson]

Example:

sysctl::base::values:
  kernel.sem:
    value: '500 256000 32 8192'

Currently it is not idempotent because sysctl -n returns 500\t256000\t32\t8192 (hard tabs) and not sspace separated as the input value. This pull request uses tr to remove any extra spaces and hard tabs and replaces them with one space in between every value.

Inspired by thias#76 but uses tr instead of sedbecause it looks nicer IMHO.

[Phil-Friderici]

Looks good to me, doesn't matter if it uses sed or tr :)