Fixed broken link checker, fixed some broken links

data/plugin_vulns.xml

@@ -1833,7 +1833,6 @@
       <title>Wp-ImageZoom - zoom.php id Parameter SQL Injection</title>
       <references>
         <osvdb>87870</osvdb>
-        <url>http://packetstormsecurity.com/files/118371/</url>
         <url>http://www.securityfocus.com/bid/56691</url>
         <url>http://xforce.iss.net/xforce/xfdb/80285</url>
       </references>
@@ -2451,7 +2450,7 @@
       <title>WP Easy Gallery &lt;= 2.7 - CSRF</title>
       <references>
         <secunia>49190</secunia>
-        <url>http://plugins.trac.wordpress.org/changeset?reponame=&amp;old=669527%40wp-easy-gallery&amp;new=669527%40wp-easy-gallery</url>
+        <url>https://plugins.trac.wordpress.org/changeset?reponame=&amp;old=669527@wp-easy-gallery&amp;new=669527@wp-easy-gallery</url>
       </references>
       <type>CSRF</type>
       <fixed_in>2.7.3</fixed_in>
@@ -7892,7 +7891,7 @@
     <vulnerability>
       <title>Social Media Widget - malicious code</title>
       <references>
-        <url>http://plugins.trac.wordpress.org/changeset?reponame=&amp;old=691839%40social-media-widget%2Ftrunk&amp;new=693941%40social-media-widget%2Ftrunk</url>
+        <url>https://plugins.trac.wordpress.org/changeset?reponame=&amp;old=691839@social-media-widget/trunk&amp;new=693941@social-media-widget/trunk</url>
         <url>http://slashdot.org/submission/2592777/top-wordpress-widget-sold-off-turned-into-seo-spambot</url>
       </references>
       <type>UNKNOWN</type>
@@ -8721,7 +8720,6 @@
     <vulnerability>
       <title>SexyBookmarks - Setting Manipulation CSRF</title>
       <references>
-        <url>http://wordpress.org/plugins/sexybookmarks/changelog/</url>
         <osvdb>95908</osvdb>
         <cve>2013-3256</cve>
         <secunia>53138</secunia>

data/theme_vulns.xml

@@ -1947,7 +1947,7 @@
     <vulnerability>
       <title>Xss In wordpress ambience theme</title>
       <references>
-        <url>http://packetstorm.igor.onlinedirect.bg/1306-exploits/wpambience-xss.txt</url>
+        <url>http://www.websecuritywatch.com/wordpress-ambience-xss/</url>
       </references>
       <type>XSS</type>
     </vulnerability>

lib/wpstools/plugins/checker/checker_plugin.rb

@@ -32,10 +32,12 @@ class CheckerPlugin < Plugin
       xml = xml(vuln_ref_file)
 
       urls = []
-      xml.xpath('//reference').each { |node| urls << node.text }
+      xml.xpath('//references/url').each { |node| urls << node.text }
 
       urls.uniq!
 
+      puts "[!] No URLs found in #{vuln_ref_file}!" if urls.empty?
+
       dead_urls       = []
       queue_count     = 0
       request_count   = 0