datastore: LocalTransaction::first_txn_num_in_block: not yet implemented

[canepat]

Running standalone rpcdaemon at commit 95a6a2d using local E3 beta1 data storage, the following RPC integration test fails:

python3 ./run_tests.py --api-list eth_call --run-single-test 1 --dump-response

Runs tests in parallel
0411. http           ::eth_call/test_01.json                                          Failed 
TEST ABORTED!
                                                                                                                  
Test time-elapsed:            0:00:00.339054
Number of executed tests:     1/1156
Number of NOT executed tests: 0
Number of success tests:      0
Number of failed tests:       1

producing the following response diff:

 {
-  result: "0x"
+  error: {
+    code: -32603
+    message: "localtransaction::first_txn_num_in_block: not yet implemented"
+  }
 }