Fix doco nit from qzrrbz@github

Milter/__init__.py

@@ -327,7 +327,9 @@ class Base(object):
   # to pass bytes to @link #header the header callback @endlink instead,
   # or trap utf-8 conversion exception, etc.
   def envfrom_bytes(self,*b):
-    s = (v.decode(encoding='utf-8',errors='surrogateescape') for v in b)
+    try:
+      s = (v.decode(encoding='utf-8') for v in b)
+    except UnicodeDecodeError: s = b
     return self.envfrom(fld,*s)
   ## Called when the SMTP client says MAIL FROM. Called by the
   # <a href="milter_api/xxfi_envfrom.html">
@@ -346,7 +348,9 @@ class Base(object):
   # to pass bytes to @link #header the header callback @endlink instead,
   # or trap utf-8 conversion exception, etc.
   def envrcpt_bytes(self,*b):
-    s = (v.decode(encoding='utf-8',errors='surrogateescape') for v in b)
+    try:
+      s = (v.decode(encoding='utf-8') for v in b)
+    except UnicodeDecodeError: s = b
     return self.envrcpt(fld,*s)
   ## Called when the SMTP client says RCPT TO. Called by the
   # <a href="milter_api/xxfi_envrcpt.html">
@@ -372,7 +376,9 @@ class Base(object):
   # Converts from utf-8 to unicode with surrogate escape.  Can be overriden 
   # to pass bytes to @link #header the header callback @endlink instead.
   def header_bytes(self,fld,val):
-    s = val.decode(encoding='utf-8',errors='surrogateescape')
+    try:
+      s = val.decode(encoding='utf-8')
+    except UnicodeDecodeError: s = val
     return self.header(fld,s)
   ## Called for each header field in the message body.
   # @param field name decoded as ascii