Remove unused nodes list

Signed-off-by: marinamoore <mnm678@gmail.com>

tuf/repository_lib.py

@@ -1640,7 +1640,6 @@ def _build_merkle_tree(fileinfodict):
   # We will build the merkle tree starting with the leaf nodes. Each
   # leaf contains snapshot information for a single metadata file.
   leaves = []
-  nodes = []
   for name, contents in sorted(fileinfodict.items()):
     if name.endswith(".json"):
       name = os.path.splitext(name)[0]
@@ -1666,9 +1665,8 @@ def _build_merkle_tree(fileinfodict):
       # Otherwise, use the next two nodes to build a new node.
       else:
         n = InternalNode(current_nodes[i], current_nodes[i+1])
-        # Add this node to the next level, and to a list of all nodes
+        # Add this node to the next level
         new_nodes.append(n)
-        nodes.append(n)
     current_nodes = new_nodes
 
   # The only node remaining in current_nodes will be the root node.