hgweb: catch util.Abort raised by addchangegroup Right now, if a pretxnchangegroup hook fails, we send some HTML error message to the client and the transaction is not rolled back (issue499). Catching util.Abort allows us to send a decent message to the client and for some reason makes the rollback complete. This patch is not perfect since it doesn't fix the reason why the transaction wasn't rolled back (maybe some circular references?). Also, the transaction is aborted only after we've sent the response back to the client and the "transaction aborted" message ends up in the logs of the web server.

changeset:   0:9c2cf2b35aa7
user:        test
date:        Mon Jan 12 13:46:40 1970 +0000
summary:     add foo

changeset:   1:3756a9556b89
tag:         tip
user:        test
date:        Mon Jan 12 13:46:41 1970 +0000
summary:     change foo

2 revisions:
9c2cf2b35aa7
3756a9556b89