Fixed handling disconnects when cancelling a hold request

Ignore-this: 9935b9cf15e7d88a4550eef8bb7f9e20

darcs-hash:20140324141100-56b4d-9e4bbd91b6f6a52a0a619040270b51951700ff93
Fixed pickling for some core objects

Ignore-this: 2b10f76833162370b74ef805bdef5451

darcs-hash:20140325121036-b22ec-a05a4f721343612b3633cdd1c0cb1be2d64d7d60
Incremented core revision

Ignore-this: e2916d3f780bd9cd4e3d8aae70f24cfd

darcs-hash:20140325131447-b22ec-891bd65d2807778d4bc586eea2a0f1ebc398c6d1