[qa] Use correct python index slices in example test

test/functional/example_test.py

@@ -111,7 +111,7 @@ def setup_network(self):
         # sync_all() should not include node2, since we're not expecting it to
         # sync.
         connect_nodes(self.nodes[0], 1)
-        self.sync_all([self.nodes[0:1]])
+        self.sync_all([self.nodes[0:2]])
 
     # Use setup_nodes() to customize the node start behaviour (for example if
     # you don't want to start all nodes at the start of the test).
@@ -135,7 +135,7 @@ def run_test(self):
 
         # Generating a block on one of the nodes will get us out of IBD
         blocks = [int(self.nodes[0].generate(nblocks=1)[0], 16)]
-        self.sync_all([self.nodes[0:1]])
+        self.sync_all([self.nodes[0:2]])
 
         # Notice above how we called an RPC by calling a method with the same
         # name on the node object. Notice also how we used a keyword argument