Follow up to #2456 - removed unnessary call to Mail::Encodings.value_decode and corrected test cases

app/models/channel/email_parser.rb

@@ -508,7 +508,7 @@ process unprocessable_mails (tmp/unprocessable_mail/*.eml) again
 
       h['x-any-recipient'] = h.values.select(&:present?).join(', ')
       h['message_id']      = imported_fields['message-id']
-      h['subject']         = Mail::Encodings.value_decode(imported_fields['subject'])
+      h['subject']         = imported_fields['subject']
       begin
         h['date'] = Time.zone.parse(mail.date.to_s) || imported_fields['date']
       rescue

spec/models/channel/email_parser_spec.rb

@@ -170,7 +170,7 @@ RSpec.describe Channel::EmailParser, type: :model do
       end
 
       it 'decode utf-8 encoded strings' do
-        expect( Mail::Encodings.value_decode('=?UTF-8?Q?Personal=C3=A4nderung?=') ).to eql( 'Personaländerung' )
+        expect( Mail::Encodings.value_decode('=?UTF-8?Q? Personal=C3=A4nderung?=') ).to eql( ' Personaländerung' )
       end
     end
   end

test/data/mail/mail077.box

@@ -5,7 +5,7 @@ Delivered-To: box@samba.example.com
 Received: from me.home (1-2-1-1.adsl.highway.example.com [1.2.1.1])
   by samba.example.com (Postfix) with ESMTPSA id C96F8500D3D
   for <info@example.com>; Thu,  3 May 2012 12:04:28 +0100 (BST)
-Subject: =?UTF-8?Q?Personal=C3=A4nderung?=
+Subject: =?UTF-8?Q? Personal=C3=A4nderung?=
 From: <John.Smith@example.com>
 Content-Type: text/plain;
   charset=iso-8859-1

test/data/mail/mail077.yml

@@ -1,2 +1,2 @@
 --- !ruby/hash:ActiveSupport::HashWithIndifferentAccess
-subject: Personaländerung
+subject: ' Personaländerung'