rewind files in flush_writes method of s3 and fog storage

lib/paperclip/storage/fog.rb

@@ -77,6 +77,7 @@ module Paperclip
       def flush_writes
         for style, file in @queued_for_write do
           log("saving #{path(style)}")
+          file.rewind
           retried = false
           begin
             directory.files.create(fog_file.merge(

lib/paperclip/storage/s3.rb

@@ -281,6 +281,7 @@ module Paperclip
         @queued_for_write.each do |style, file|
           begin
             log("saving #{path(style)}")
+            file.rewind
             acl = @s3_permissions[style] || @s3_permissions[:default]
             acl = acl.call(self, style) if acl.respond_to?(:call)
             write_options = {

test/storage/fog_test.rb

@@ -116,6 +116,11 @@ class FogTest < Test::Unit::TestCase
         assert_equal 0, @dummy.avatar.to_file.pos
       end
 
+      should "rewind file in flush_writes" do
+        @dummy.avatar.queued_for_write.each { |style, file| file.expects(:rewind).with() }
+        @dummy.save
+      end
+
       should "pass the content type to the Fog::Storage::AWS::Files instance" do
         Fog::Storage::AWS::Files.any_instance.expects(:create).with do |hash|
           hash[:content_type]

test/storage/s3_test.rb

@@ -341,6 +341,12 @@ class S3Test < Test::Unit::TestCase
         @dummy.avatar.to_file.seek(10)
         assert_equal 0, @dummy.avatar.to_file.pos
       end
+
+    should "rewind file in flush_writes" do
+      @dummy.avatar.queued_for_write.each { |style, file| file.expects(:rewind).with() }
+      @dummy.save
+    end
+
   end
 
   context "Generating a secure url with an expiration" do