issue2551178 - fix Traceback in Apache WSGI

Alternate way to fix issue I hope. We do want to delete the
headers, not just emit them with no value.

Author: rouilj

CHANGES.txt

@@ -51,6 +51,7 @@ Fixed:
   now include a suffix indicating the content-encoding used to send
   the data per rfc7232. Properly validate any form of ETag suffixed or
   non-suffixed for If-Match.
+- issue2551178 - fix Traceback in Apache WSGI - during file upload
 
 Features:
 

roundup/cgi/client.py

@@ -2492,9 +2492,15 @@ def write_file(self, filename):
         self.write(content)
 
     def setHeader(self, header, value):
-        """Override a header to be returned to the user's browser.
+        """Override or delete a header to be returned to the user's browser.
         """
-        self.additional_headers[header] = value
+        if value is None:
+            try:
+                del(self.additional_headers[header])
+            except KeyError:
+                pass
+        else:
+            self.additional_headers[header] = value
 
     def header(self, headers=None, response=None):
         """Put up the appropriate header.

roundup/rest.py

@@ -1256,11 +1256,11 @@ def post_collection_inner(self, class_name, input):
 
         self.client.setHeader(
             "Allow",
-            ""
+            None
         )
         self.client.setHeader(
             "Access-Control-Allow-Methods",
-            ""
+            None
         )
 
         # set the response body