scripted-diff: Rename mininode to p2p

-BEGIN VERIFY SCRIPT-
sed -i 's/\.mininode/\.p2p/g' $(git grep -l "mininode")
git mv test/functional/test_framework/mininode.py test/functional/test_framework/p2p.py
-END VERIFY SCRIPT-

test/functional/feature_assumevalid.py

@@ -42,7 +42,7 @@ from test_framework.messages import (
     msg_block,
     msg_headers,
 )
-from test_framework.mininode import P2PInterface
+from test_framework.p2p import P2PInterface
 from test_framework.script import (CScript, OP_TRUE)
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal