Fixed handling options[:persistent] in some cases

Removed useless
@persistent = options[:persistent]  || true

It prevented @persistent from being set to `false`

lib/fog/aws/cdn.rb

@@ -88,7 +88,7 @@ module Fog
           @hmac       = Fog::HMAC.new('sha1', @aws_secret_access_key)
           @host       = options[:host]      || 'cloudfront.amazonaws.com'
           @path       = options[:path]      || '/'
-          @persistent = options[:persistent] || true
+          @persistent = options.fetch(:persistent, true)
           @port       = options[:port]      || 443
           @scheme     = options[:scheme]    || 'https'
           @version    = options[:version]  || '2010-11-01'

lib/fog/aws/dns.rb

@@ -90,7 +90,7 @@ module Fog
           @hmac       = Fog::HMAC.new('sha1', @aws_secret_access_key)
           @host       = options[:host]        || 'route53.amazonaws.com'
           @path       = options[:path]        || '/'
-          @persistent = options[:persistent].nil?  || options[:persistent]
+          @persistent = options.fetch(:persistent, true)
           @port       = options[:port]        || 443
           @scheme     = options[:scheme]      || 'https'
           @version    = options[:version]     || '2012-02-29'

lib/fog/aws/storage.rb

@@ -271,7 +271,7 @@ module Fog
               "s3-#{options[:region]}.amazonaws.com"
             end
             @path       = options[:path]        || '/'
-            @persistent = options[:persistent]  || true
+            @persistent = options.fetch(:persistent, true)
             @port       = options[:port]        || 443
             @scheme     = options[:scheme]      || 'https'
           end

lib/fog/dnsmadeeasy/dns.rb

@@ -85,7 +85,7 @@ module Fog
           @dnsmadeeasy_secret_key = options[:dnsmadeeasy_secret_key]
           @connection_options = options[:connection_options] || {}
           @host       = options[:host]        || 'api.dnsmadeeasy.com'
-          @persistent = options[:persistent]  || true
+          @persistent = options.fetch(:persistent, true)
           @port       = options[:port]        || 80 #443 Not yet
           @scheme     = options[:scheme]      || 'http' #'https Not yet
           @connection = Fog::Connection.new("#{@scheme}://#{@host}:#{@port}", @persistent, @connection_options)

lib/fog/google/storage.rb

@@ -192,7 +192,7 @@ module Fog
           @connection_options = options[:connection_options] || {}
           @hmac = Fog::HMAC.new('sha1', @google_storage_secret_access_key)
           @host = options[:host] || 'commondatastorage.googleapis.com'
-          @persistent = options[:persistent]  || true
+          @persistent = options.fetch(:persistent, true)
           @port       = options[:port]        || 443
           @scheme     = options[:scheme]      || 'https'
           @connection = Fog::Connection.new("#{@scheme}://#{@host}:#{@port}", @persistent, @connection_options)

lib/fog/ninefold/storage.rb

@@ -54,7 +54,7 @@ module Fog
 
           @connection_options = options[:connection_options] || {}
           @hmac               = Fog::HMAC.new('sha1', @ninefold_storage_secret_decoded)
-          @persistent         = options[:persistent] || true
+          @persistent = options.fetch(:persistent, true)
 
           @connection = Fog::Connection.new("#{Fog::Storage::Ninefold::STORAGE_SCHEME}://#{Fog::Storage::Ninefold::STORAGE_HOST}:#{Fog::Storage::Ninefold::STORAGE_PORT}", @persistent, @connection_options)
         end