fix(runner): Use current node version if unknown commit

.github/workflows/integration.yml

@@ -15,7 +15,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
         with:
-          path: "testnet-load-generator"
+          path: testnet-load-generator
 
       - name: Get the appropriate agoric-sdk branch
         id: get-sdk-branch
@@ -35,11 +35,11 @@ jobs:
             console.log(branch);
             return branch;
 
-      - name: Check out agoric-sdk
+      - name: Checkout agoric-sdk
         uses: actions/checkout@v2
         with:
           repository: Agoric/agoric-sdk
-          submodules: "true"
+          submodules: 'true'
           path: agoric-sdk
           ref: ${{steps.get-sdk-branch.outputs.result}}
 

start.sh

@@ -45,7 +45,9 @@ export PATH="$AGORIC_BIN_DIR:$PATH"
 
 if [ ! -f "${OUTPUT_DIR}/.nvmrc" ] ; then
     SDK_NODE16_REVISION=475d7ff1eb2371aa9e0c0dc7a50644089db351f6
-    if ! git -C "${SDK_SRC}" merge-base --is-ancestor $SDK_NODE16_REVISION $SDK_FULL_REVISION ; then
+    if git -C "${SDK_SRC}" cat-file -e $SDK_NODE16_REVISION^{commit} && \
+      ! git -C "${SDK_SRC}" merge-base --is-ancestor $SDK_NODE16_REVISION $SDK_FULL_REVISION
+    then
         echo "lts/fermium" > "${OUTPUT_DIR}/.nvmrc"
     fi
     if [ -n "$NVM_RC_VERSION" ]; then