Allow make clean to work when svn-test-work is a mounted ramdisk.
Allow make clean to work when svn-test-work is a mounted ramdisk.

If you follow the instructions in subversion/tests/cmdline/README then make clean
fails since it can't remove svn-test-work.

* Makefile.in
  (check-clean): find nodes under svn-test-work and remove them rather than
    the directory itself.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1421636 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion