bottle: fix --merge with multiple formulae.

Library/Homebrew/cmd/bottle.rb

@@ -8,6 +8,7 @@ class BottleMerger < Formula
   # a Formula. This object is used to access the Formula bottle DSL to merge
   # multiple outputs of `brew bottle`.
   url '1'
+  def self.reset_bottle; @bottle = Bottle.new; end
 end
 
 module Homebrew extend self
@@ -104,17 +105,30 @@ module Homebrew extend self
     end
   end
 
-  def bottle
-    if ARGV.include? '--merge'
+  def merge
+    merge_hash = {}
     ARGV.named.each do |argument|
-        bottle_block = IO.read(argument)
+      formula_name = bottle_filename_formula_name argument
+      merge_hash[formula_name] ||= []
+      bottle_block = IO.read argument
+      merge_hash[formula_name] << bottle_block
+    end
+    merge_hash.keys.each do |formula_name|
+      BottleMerger.reset_bottle
+      ohai formula_name
+      bottle_blocks = merge_hash[formula_name]
+      bottle_blocks.each do |bottle_block|
         BottleMerger.class_eval bottle_block
       end
       bottle = BottleMerger.new.bottle
       bottle_output bottle if bottle
+    end
     exit 0
   end
 
+  def bottle
+    merge if ARGV.include? '--merge'
+
     ARGV.formulae.each do |f|
       bottle_formula f
     end