Description: install doc in the right place for Debian

--- a/setup.py
+++ b/setup.py
@@ -62,7 +62,7 @@ if sys.version >= '3':
 else:
     packages.append('networkx.external.decorator.decorator2')
 
-docdirbase  = 'share/doc/networkx-%s' % version
+docdirbase  = 'share/doc/python-networkx'
 # add basic documentation 
 data = [(docdirbase, glob("*.txt"))]
 # add examples
