abort: added support for graft This adds support of `graft` to `hg abort` plan. The patch creates a seperate function `cmdutil.hgabortgraft` so that abort logic for graft can be called independently. This logic is registered to the statedetection API as `abortfunc`. Results are shown as tests. Differential Revision: https://phab.mercurial-scm.org/D6567