fix(rpc-json): enable X11 block hash for Dash

Enable dash  so BlockHash and header.block_hash()
match Dash RPC hits	command
   1	/usr/bin/git fields; fixes header/hash assertions in integration tests.

Author: PastaPastaPasta

rpc-json/Cargo.toml

@@ -26,6 +26,6 @@ serde_repr = "0.1"
 hex = { version="0.4", features=["serde"]}
 
 key-wallet = { path = "../key-wallet", features=["serde"] }
-dashcore = { path = "../dash", features=["std", "secp-recovery", "rand-std", "signer", "serde"], default-features = false }
+dashcore = { path = "../dash", features=["std", "secp-recovery", "rand-std", "signer", "serde", "core-block-hash-use-x11"], default-features = false }
 
 bincode = { version = "=2.0.0-rc.3", features = ["serde"] }