make update quieter when nothing is wrong

sometimes when i am going around in my history, i get long lists of
errors from the update command. this patch will fix that. i tried to
make the code style the same like the rest of the code.

mercurial/localrepo.py

@@ -1265,7 +1265,9 b' class localrepository:'
             try:
                 os.unlink(self.wjoin(f))
             except OSError, inst:
-                self.ui.warn("update failed to remove %s: %s!\n" % (f, inst))
+                if inst.errno != errno.ENOENT:
+                    self.ui.warn("update failed to remove %s: %s!\n" %
+                                 (f, inst.strerror))
             # try removing directories that might now be empty
             try: os.removedirs(os.path.dirname(self.wjoin(f)))
             except: pass