FIX: support emails in with weird encoding

lib/email/receiver.rb

@@ -166,7 +166,9 @@ module Email
 
     def try_to_encode(string, encoding)
       string.encode("UTF-8", encoding)
-    rescue Encoding::InvalidByteSequenceError, Encoding::UndefinedConversionError
+    rescue Encoding::InvalidByteSequenceError,
+           Encoding::UndefinedConversionError,
+           Encoding::ConverterNotFoundError
       nil
     end
 

spec/components/email/receiver_spec.rb

@@ -109,6 +109,9 @@ describe Email::Receiver do
 
       expect { process(:chinese_reply) }.to change { topic.posts.count }
       expect(topic.posts.last.raw).to eq("您好！ 你今天好吗？")
+
+      expect { process(:reply_with_weird_encoding) }.to change { topic.posts.count }
+      expect(topic.posts.last.raw).to eq("This is a reply with a weird encoding.")
     end
 
     it "prefers text over html" do

spec/fixtures/emails/reply_with_weird_encoding.eml

@@ -0,0 +1,9 @@
+Return-Path: <discourse@bar.com>
+From: Foo Bar <discourse@bar.com>
+To: reply+4f97315cc828096c9cb34c6f1a0d6fe8@bar.com
+Date: Fri, 15 Jan 2016 00:12:43 +0100
+Message-ID: <42@foo.bar.mail>
+Mime-Version: 1.0
+Content-Type: text/plain; charset=unicode-1-1-utf-7
+
+This is a reply with a weird encoding.