test-remove: fix \ vs. / issues on Windows

This part of the test failed with

     $ hg rm --after d1
  -  removing d1/a
  +  removing d1\a

on Windows.

tests/test-remove.t

@@ -275,7 +275,7 b' handling of untracked directories and mi'
   $ hg add d1/a
   $ rm d1/a
   $ hg rm --after d1
-  removing d1/a
+  removing d1/a (glob)
   $ hg rm --after nosuch
   nosuch: No such file or directory
   [1]