scmutil: fix erroneous Abort call

This fixes d13913355390 (affected Windows only).

mercurial/scmutil.py

@@ -128,7 +128,7 b' class opener(object):'
     def __call__(self, path, mode="r", text=False, atomictemp=False):
         r = util.checkosfilename(path)
         if r:
-            raise Abort("%s: %r" % (r, path))
+            raise util.Abort("%s: %r" % (r, path))
         self.auditor(path)
         f = os.path.join(self.base, path)