libdwarf: remove use of hide_files()

- This was a nasty workaround due to the way our compiler wrappers used
  to work.  We don't want to have to modify our elfutils installation to
  install libdwarf.

- Since cd9691de5, we no longer need this because the package will always
  come before dependencies in our include order.

lib/spack/llnl/util/filesystem.py

@@ -60,7 +60,6 @@
     'fix_darwin_install_name',
     'force_remove',
     'force_symlink',
-    'hide_files',
     'install',
     'install_tree',
     'is_exe',
@@ -392,18 +391,6 @@ def replace_directory_transaction(directory_name, tmp_root=None):
         tty.debug('TEMPORARY DIRECTORY DELETED [{0}]'.format(tmp_dir))
 
 
-@contextmanager
-def hide_files(*file_list):
-    try:
-        baks = ['%s.bak' % f for f in file_list]
-        for f, bak in zip(file_list, baks):
-            shutil.move(f, bak)
-        yield
-    finally:
-        for f, bak in zip(file_list, baks):
-            shutil.move(bak, f)
-
-
 def hash_directory(directory):
     """Hashes recursively the content of a directory.
 

var/spack/repos/builtin/packages/libdwarf/package.py

@@ -61,14 +61,6 @@ def patch(self):
         filter_file(r'^typedef struct Elf Elf;$', '', 'libdwarf/libdwarf.h.in')
 
     def install(self, spec, prefix):
-
-        # elfutils contains a dwarf.h that conflicts with libdwarf's
-        # TODO: we should remove this when we can modify the include order
-        hide_list = []
-        if spec.satisfies('^elfutils'):
-            dwarf_h = join_path(spec['elfutils'].prefix, 'include/dwarf.h')
-            hide_list.append(dwarf_h)
-        with hide_files(*hide_list):
         # dwarf build does not set arguments for ar properly
         make.add_default_arg('ARFLAGS=rcs')