Remove the offset field from ap_bucket type. This is a file bucket

specific value, and therefore it belongs in the ap_bucket_file type,
which was also created with this commit.  ap_bucket needs to be as generic
as possible to make it easily extensible, which means we have to keep
the generic ap_bucket type very separate from ap_bucket_foo.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@86568 13f79535-47bb-0310-9956-ffa450edef68