Creation of a function xml instead of a hack for Nokogiri::XML

lib/wpscan/vulnerable.rb

@@ -23,7 +23,7 @@ class Vulnerable
 
   # @return an array of WpVulnerability (can be empty)
   def vulnerabilities
-    xml             = Nokogiri::XML(File.open(@vulns_file))
+    xml             = xml(@vulns_file)
     vulnerabilities = []
 
     xml.xpath(@vulns_xpath).each do |node|

lib/wpscan/wp_enumerator.rb

@@ -121,7 +121,7 @@ class WpEnumerator
 
     # Timthumbs have no XML file
     unless type =~ /timthumbs/i
-      xml = Nokogiri::XML(File.open(vulns_file))
+      xml = xml(vulns_file)
 
       # We check if the plugin name from the plugin_vulns_file is already in targets, otherwise we add it
       xml.xpath(options[:vulns_xpath_2]).each do |node|

lib/wpscan/wp_version.rb

@@ -146,7 +146,7 @@ class WpVersion < Vulnerable
     version_xml = options[:version_xml] || WP_VERSIONS_FILE # needed for rpsec
     wp_content  = options[:wp_content_dir]
     wp_plugins  = "#{wp_content}/plugins"
-    xml         = Nokogiri::XML(File.open(version_xml))
+    xml         = xml(version_xml)
 
     xml.xpath('//file').each do |node|
       file_src = node.attribute('src').text