hdf5

[svn-r4994] 
Purpose:
    Bug Fix
Description:
    The doc tree wasn't being cleaned up all the way. Directories would
    be left in there and some examples/Tutorial files weren't cleaned up
    correctly.
Solution:
    Have it remove the whole directory tree of the HDF5 documents

        $(RM) -r $(DOCDIR)/hdf5

Platforms tested:
    Linux