buildkite: add submodule fetching

Author: deepfire

.buildkite/nightly.yml

@@ -1,6 +1,7 @@
 steps:
   - label: 'Acceptance Tests - mainnet'
     command:
+      - git submodule update --init --recursive
       - nix-build -A acceptanceTests.mainnet.full -o acceptance-tests-mainnet-full.sh
       - echo "+++ Syncing mainnet blockchain"
       - ./acceptance-tests-mainnet-full.sh
@@ -10,6 +11,7 @@ steps:
 
   - label: 'Acceptance Tests - testnet'
     command:
+      - git submodule update --init --recursive
       - nix-build -A acceptanceTests.testnet.full -o acceptance-tests-testnet-full.sh
       - echo "+++ Syncing testnet blockchain"
       - ./acceptance-tests-testnet-full.sh

.buildkite/pipeline.yml

@@ -15,6 +15,6 @@ steps:
       system: x86_64-linux
 
   - label: 'triggerShutdown test'
-    command: "rm -rf test-state ; nix-shell node-ipc/shell.nix --run 'node node-ipc/server.js'"
+    command: "git submodule update --init --recursive ; rm -rf test-state ; nix-shell node-ipc/shell.nix --run 'node node-ipc/server.js'"
     agents:
       system: x86_64-linux