Update tree to 1.5.3

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/tree.rb

@@ -1,9 +1,9 @@
 require 'formula'
 
 class Tree <Formula
-  @url='ftp://mama.indstate.edu/linux/tree/tree-1.5.2.2.tgz'
+  @url='ftp://mama.indstate.edu/linux/tree/tree-1.5.3.tgz'
   @homepage='http://mama.indstate.edu/users/ice/tree/'
-  @md5='a7731a898e2c0d7e422a57a84ffbb06c'
+  @md5='c07ce9065667a23f27aca4de8ecccb10'
 
   def install
     system "#{ENV.cc} #{ENV['CFLAGS']} -o tree tree.c strverscmp.c"