Fixing two issues in jenkins::config

1) For the Debian family (Checked Debian Wheezy and Ubuntu Precise) the defaults folder is in /etc/default instead of /etc/defaults
2) Removed prefixing of JENKINS_ on each variable as it removes flexibilty. If a user wants to add that - they can. This now enables me to set things like
HTTP_PORT correctly. Also - as a word of caution, file_line adds new resources to the end of the file - This may cause issues (For example, if HTTP_PORT is set after
JENKINS_ARGS then HTTP_PORT will not actually be read in, as JENKINS_ARGS calls it.

Tested on Ubuntu Precise 12.04 (Only checked the default part on Wheezy, didn't test - Can't imagine it being any different though)

  class { 'jenkins':
    config_hash => {
      'HTTP_PORT' => { 'value' => 2222 }
    }
  }

Was applied to my test node successfully.
Fixing Test (They were all due to linter erroring out on trailing whitespace)

All "errors" were caused by the linter giving an exit code on trailing white space. Went ahead and removed it
all - Also cleaned up as many warning as I could for lines > 80 - Left a few but as they're strings I'm not really sure
if forcing it under 80 would make it look any cleaner.
Merge pull request #1 from thomasbiddle/jenkins_config_fix

Fixing two issues in jenkins::config