isync: use spec deps

Formula/isync.rb

@@ -5,15 +5,15 @@ class Isync < Formula
   url 'http://downloads.sourceforge.net/project/isync/isync/1.0.6/isync-1.0.6.tar.gz'
   sha1 '5cd7403722584b9677fc6a4185c0b9a00f153453'
 
-  head 'git://isync.git.sourceforge.net/gitroot/isync/isync'
+  head do
+    url 'git://isync.git.sourceforge.net/gitroot/isync/isync'
 
-  depends_on 'berkeley-db'
-
-  if build.head?
     depends_on :autoconf
     depends_on :automake
   end
 
+  depends_on 'berkeley-db'
+
   def patches
     # Add "PassCommand" config:
     # http://sourceforge.net/p/isync/patches/12/