Fixed header normalization for JavaMail update

Author: dghgit

mail/src/main/java/org/bouncycastle/mail/smime/SMIMEGenerator.java

@@ -133,11 +133,6 @@ protected MimeBodyPart makeContentBodyPart(
         //
         try
         {
-            message.removeHeader("Message-Id");
-            message.removeHeader("Mime-Version");
-
-            message.saveChanges();
-
             // JavaMail has a habit of reparsing some content types, if the bodypart is
             // a multipart it might be signed, we rebuild the body part using the raw input stream for the message.
             try
@@ -183,7 +178,19 @@ private void extractHeaders(MimeBodyPart content, MimeMessage message)
         {
             Header hdr = (Header)e.nextElement();
 
-            content.addHeader(hdr.getName(), hdr.getValue());
+            // normalise some headers
+            if (hdr.getName().equals("Message-Id"))
+            {
+                content.addHeader("Message-ID", hdr.getValue());
+            }
+            else if (hdr.getName().equals("Mime-Version"))
+            {
+                content.addHeader("MIME-Version", hdr.getValue());
+            }
+            else
+            {
+                content.addHeader(hdr.getName(), hdr.getValue());
+            }
         }
     }