(maint) Update VMPooler files with fixes for Rubocop violations

This commit updates vmpooler.rb, api.rb and providers.rb with style changes as
per rubocop style violations.

This commit also updates the rubocop configuration to always use LF line endings
even on Windows as rubocop was expecting CRLF even though git is configured
for LF.

.rubocop.yml

@@ -9,6 +9,8 @@ AllCops:
     - 'scripts/**/*'
     - 'spec/**/*'
     - 'vendor/**/*'
+    - Gemfile
+    - Rakefile
 
 Style/Documentation:
   Enabled: false
@@ -58,3 +60,7 @@ Style/ConditionalAssignment:
 Next:
   Enabled: false
 
+# Enforce LF line endings, even when on Windows
+Style/EndOfLine:
+  EnforcedStyle: lf
+

lib/vmpooler.rb

@@ -12,7 +12,7 @@ module Vmpooler
   require 'yaml'
   require 'set'
 
-  %w(api graphite logger pool_manager vsphere_helper statsd dummy_statsd providers).each do |lib|
+  %w[api graphite logger pool_manager vsphere_helper statsd dummy_statsd providers].each do |lib|
     begin
       require "vmpooler/#{lib}"
     rescue LoadError

lib/vmpooler/api.rb

@@ -30,7 +30,7 @@ module Vmpooler
     use Vmpooler::Dashboard
 
     # Load API components
-    %w(helpers dashboard reroute v1).each do |lib|
+    %w[helpers dashboard reroute v1].each do |lib|
       begin
         require "api/#{lib}"
       rescue LoadError

lib/vmpooler/providers.rb

@@ -1,4 +1,4 @@
-%w(base dummy vsphere).each do |lib|
+%w[base dummy vsphere].each do |lib|
   begin
     require "vmpooler/providers/#{lib}"
   rescue LoadError