[build] update nim-datastore

also make changes to `codex/codex.nim` and tests for SQLiteStore re: changes in
nim-datastore

closes #178

codex/codex.nim

@@ -133,7 +133,15 @@ proc new*(T: type CodexServer, config: CodexConf): T =
 
     wallet = WalletRef.new(EthPrivateKey.random())
     network = BlockExcNetwork.new(switch)
-    localStore = SQLiteStore.new(config.dataDir / "repo", cache = cache)
+    repoDir = config.dataDir / "repo"
+
+  if io2.createPath(repoDir).isErr:
+    trace "Unable to create data directory for block store", dataDir = repoDir
+    raise (ref Defect)(
+      msg: "Unable to create data directory for block store: " & repoDir)
+
+  let
+    localStore = SQLiteStore.new(repoDir, cache = cache)
     peerStore = PeerCtxStore.new()
     pendingBlocks = PendingBlocksManager.new()
     discovery = DiscoveryEngine.new(localStore, peerStore, network, blockDiscovery, pendingBlocks)

tests/codex/stores/testsqlitestore.nim

@@ -38,6 +38,7 @@ proc runSuite(cache: bool) =
     setup:
       removeDir(repoDir)
       require(not dirExists(repoDir))
+      createDir(repoDir)
 
       if cache:
         store = SQLiteStore.new(repoDir)

vendor/nim-datastore

@@ -1 +1 @@
-Subproject commit d5d986c0140a46e957d9a88df40b7ce7dad424f3
+Subproject commit 2769ce1de21e595e712fd1df7a195c34cd5d18de