Remove duplicated else if "dns-prefetch" branch

Source/core/html/LinkRelAttribute.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 53 matching lines @@
     else if (equalIgnoringCase(rel, "apple-touch-icon"))
         m_iconType = TouchIcon;
     else if (equalIgnoringCase(rel, "apple-touch-icon-precomposed"))
         m_iconType = TouchPrecomposedIcon;
 #endif
     else if (equalIgnoringCase(rel, "dns-prefetch"))
         m_isDNSPrefetch = true;
     else if (equalIgnoringCase(rel, "alternate stylesheet") || equalIgnoringCase(rel, "stylesheet alternate")) {
         m_isStyleSheet = true;
         m_isAlternate = true;
-    } else if (equalIgnoringCase(rel, "dns-prefetch")) {
-        m_isDNSPrefetch = true;
     } else if (equalIgnoringCase(rel, "import")) {
         m_isImport = true;
     } else {
         // Tokenize the rel attribute and set bits based on specific keywords that we find.
         String relCopy = rel;
         relCopy.replace('\n', ' ');
         Vector<String> list;
         relCopy.split(' ', list);
         Vector<String>::const_iterator end = list.end();
         for (Vector<String>::const_iterator it = list.begin(); it != end; ++it) {
@@ skipping 13 matching lines @@
               m_isLinkPrefetch = true;
             else if (equalIgnoringCase(*it, "subresource"))
               m_isLinkSubresource = true;
             else if (equalIgnoringCase(*it, "prerender"))
               m_isLinkPrerender = true;
         }
     }
 }
 
 }