graft-state: save --base in graft's state, fixing bug with graft --continue Without this change, running graft --continue after grafting a merge commit using --base (and encountering conflicts) will output "skipping ungraftable merge revision" even though we specified a base in the initial graft command. Graft's improve behaviour is reflected in test-graft.t. Differential Revision: https://phab.mercurial-scm.org/D8578