dirstate: forward `remove` call to newer `API`
The `_remove` method was only called in the deprecated `remove` function. We
merge the two and express it in terms of call to new API methods.
Differential Revision: https://phab.mercurial-scm.org/D11314
Added signature for changeset
86a60679cf61
Added tag 5.9.1 for changeset
86a60679cf61