workingctx: add _poststatus method to call _filtersuspectsymlink...
workingctx: add _poststatus method to call _filtersuspectsymlink
With this patch, we are one step closer to removing 'if ... else' logic in
localrepo.status for testing if the context is the working directory or
not. Future patches will replace those blocks of code with a call to the
context's _poststatus hook so that each context object will do the right thing
depending on the situation.
