Merge #14543: [QA] minor p2p_sendheaders fix of height in coinbase

1cdb9bb minor p2p_sendheaders fix of height in coinbase (Gregory Sanders)

Pull request description:

  > \# Now announce a header that forks the last two blocks

  Doesn't effect any behavior since BIP34 isn't active in regtest for many blocks.

Tree-SHA512: 3f214b956a94250bb640f63b6ff707930e1d4cb8df1bbf0fef4012d89a94bafbde0d7b42bbe7113ec33810169281c22c6e389445921d99decb74aa56e87a0f27

Author: MarcoFalke

test/functional/p2p_sendheaders.py

@@ -490,7 +490,7 @@ def test_nonnull_locators(self, test_node, inv_node):
 
         # Now announce a header that forks the last two blocks
         tip = blocks[0].sha256
-        height -= 1
+        height -= 2
         blocks = []
 
         # Create extra blocks for later