mail/spamass-milter: Fix a problem where DKIM results would always fail.

Imported a patch submitted to upstream to fix CR/LF handling [1].
Also see [2].

[1] https://savannah.nongnu.org/bugs/index.php?57626
[2] https://bz.apache.org/SpamAssassin/show_bug.cgi?id=7785

Reported by:  Keith Clarke

mail/spamass-milter/Makefile

@@ -3,7 +3,7 @@
 
 PORTNAME=	spamass-milter
 PORTVERSION=	0.4.0
-PORTREVISION=	3
+PORTREVISION=	4
 CATEGORIES=	mail
 MASTER_SITES=	SAVANNAH/spamass-milt
 

mail/spamass-milter/files/patch-spamass-milter.cpp

@@ -0,0 +1,27 @@
+--- spamass-milter.cpp
++++ spamass-milter.cpp
+@@ -1206,7 +1206,23 @@ mlfi_header(SMFICTX* ctx, char* headerf,
+     assassin->set_subject(headerv);
+ 
+   // assemble header to be written to SpamAssassin
+-  string header = string(headerf) + ": " + headerv + "\r\n";
++  string header = headerv;
++
++  // Replace all LF with CRLF
++  // As milter documentation says:
++  //     headerv    Header field value.  The content of the header may
++  //       include folded white space, i.e., multiple lines with following
++  //       white space where lines are separated by LF (not CR/LF).  The
++  //       trailing line terminator (CR/LF) is removed.
++  // Need to make sure folded header line breaks are sent to SA as CRLF
++  string::size_type idx = header.size();
++  while ( (idx = header.rfind("\n", idx)) != string::npos )
++  {
++     header.replace(idx,1,"\r\n");
++  }
++
++  // final assembly
++  header = string(headerf) + ": " + header + "\r\n";
+  
+   try {
+     // write to SpamAssassin client