Index: Lib/rfc822.py
===================================================================
--- Lib/rfc822.py	(revision 57634)
+++ Lib/rfc822.py	(working copy)
@@ -160,8 +160,7 @@
             if headerseen and line[0] in ' \t':
                 # It's a continuation line.
                 lst.append(line)
-                x = (self.dict[headerseen] + "\n " + line.strip())
-                self.dict[headerseen] = x.strip()
+                self.dict[headerseen] += line.rstrip()
                 continue
             elif self.iscomment(line):
                 # It's a comment.  Ignore it.