dirstate.status: return explicit unknown files even when not asked

dirstate.walk will return unknown files that were explicitly requested, even
if listunknown is false. There's no point in dropping these files on the
floor in dirstate.status.

This has no effect on any current callers, because all of them assume the
unknown list is empty and ignore it. Future callers may find it useful,
though.

mercurial/dirstate.py

@@ -815,7 +815,7 b' class dirstate(object):'
                 if (listignored or mexact(fn)) and dirignore(fn):
                     if listignored:
                         iadd(fn)
-                elif listunknown:
+                else:
                     uadd(fn)
                 continue