Install the documentation in the expected Debian directory

Index: python-pygraphviz-1.0/setup.py
===================================================================
--- python-pygraphviz-1.0.orig/setup.py	2010-09-16 22:53:44.265277906 +0200
+++ python-pygraphviz-1.0/setup.py	2010-09-16 22:54:06.741278023 +0200
@@ -98,7 +98,7 @@
 sys.path.pop(0)
 
 packages = ["pygraphviz","pygraphviz.tests"]
-docdirbase  = 'share/doc/pygraphviz-%s' % release.version
+docdirbase  = 'share/doc/python-pygraphviz'
 data = [(docdirbase, glob("*.txt")),
         (os.path.join(docdirbase, 'examples'),glob("examples/*.py")),
         (os.path.join(docdirbase, 'examples'),glob("examples/*.dat")),
