elinks: use spec deps

Formula/elinks.rb

@@ -5,15 +5,15 @@ class Elinks < Formula
   url 'http://elinks.or.cz/download/elinks-0.11.7.tar.bz2'
   sha1 'd13edc1477d0ab32cafe7d3c1f3a23ae1c0a5c54'
 
-  head 'http://elinks.cz/elinks.git'
-
   devel do
     url 'http://elinks.cz/download/elinks-0.12pre6.tar.bz2'
     version '0.12pre6'
     sha1 '3517795e8a390cb36ca249a5be6514b9784520a5'
   end
 
-  if build.head?
+  head do
+    url 'http://elinks.cz/elinks.git'
+
     depends_on :automake
     depends_on :libtool
   end