[xml] python/Makefile.am patch for libxslt 1.0.15

[Albert Chin <xml thewrittenword com>]

It's not always the case that $(datadir) == $(prefix)/share.

-- 
albert chin (china thewrittenword com)

-- snip snip
--- python/Makefile.am.orig     Wed Mar 27 00:53:32 2002
+++ python/Makefile.am  Wed Mar 27 00:53:44 2002
@@ -8,7 +8,7 @@
         $(LIBXML_CFLAGS) \
        -I$(top_srcdir)
 
-DOCS_DIR = $(prefix)/share/doc/libxslt-python-$(LIBXSLT_VERSION)
+DOCS_DIR = $(datadir)/doc/libxslt-python-$(LIBXSLT_VERSION)
 # libxsltclass.txt is generated
 DOCS = TODO