fsmonitor: use next() instead of .next()

This is needed for Python 3 compatibility.

Differential Revision: https://phab.mercurial-scm.org/D7212

hgext/fsmonitor/__init__.py

@@ -504,9 +504,9 b' def overridewalk(orig, self, match, subr'
     for f in auditfail:
         results[f] = None
 
-    nf = iter(auditpass).next
+    nf = iter(auditpass)
     for st in util.statfiles([join(f) for f in auditpass]):
-        f = nf()
+        f = next(nf)
         if st or f in dmap:
             results[f] = st