Remove Content-Length HTTP header from 304 responses which violates RFC 2616....

Remove Content-Length HTTP header from 304 responses which violates RFC 2616. This was a workaround for a (fixed) apache proxy-cache bug. (Issue #544)

lib/python/OFS/Image.py

@@ -12,7 +12,7 @@
 ##############################################################################
 """Image object"""
 
-__version__='$Revision: 1.151 $'[11:-2]
+__version__='$Revision: 1.152 $'[11:-2]
 
 import Globals, struct
 from OFS.content_types import guess_content_type
@@ -150,12 +150,9 @@ class File(Persistent, Implicit, PropertyManager,
                 else:
                     last_mod = long(0)
                 if last_mod > 0 and last_mod <= mod_since:
-                    # Set header values since apache caching will return
-                    # Content-Length of 0 in response if size is not set here
                     RESPONSE.setHeader('Last-Modified',
                                        rfc1123_date(self._p_mtime))
                     RESPONSE.setHeader('Content-Type', self.content_type)
-                    RESPONSE.setHeader('Content-Length', self.size)
                     RESPONSE.setHeader('Accept-Ranges', 'bytes')
                     RESPONSE.setStatus(304)
                     return True