Change text from no such <class> node <node id> to drop "node"

This brings it in line with how same error is expressed in
anydbm. Allows me to test more easily with one pattern to search for
regardless of backend.

Author: rouilj

roundup/backends/rdbms_common.py

@@ -1199,7 +1199,7 @@ def getnode(self, classname, nodeid, fetch_multilinks=True):
 
         values = self.sql_fetchone()
         if values is None:
-            raise IndexError('no such %s node %s' % (classname, nodeid))
+            raise IndexError('no such %s %s' % (classname, nodeid))
 
         # make up the node
         node = {}