add logs subscription detection fix (#426)

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumEgressSubscription.kt

@@ -31,7 +31,12 @@ open class EthereumEgressSubscription(
     open val logs = ConnectLogs(upstream, scheduler)
     override fun getAvailableTopics(): List<String> {
         val subs = if (upstream.getCapabilities().contains(Capability.WS_HEAD)) {
-            listOf(METHOD_NEW_HEADS, METHOD_LOGS)
+            // we can't use logs without eth_getLogs method available
+            if (upstream.getMethods().isAvailable("eth_getLogs")) {
+                listOf(METHOD_NEW_HEADS, METHOD_LOGS)
+            } else {
+                listOf(METHOD_NEW_HEADS)
+            }
         } else {
             listOf()
         }

src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumEgressSubscriptionSpec.groovy

@@ -200,6 +200,14 @@ class EthereumEgressSubscriptionSpec extends Specification {
         def ethereumSubscribe3 = new EthereumEgressSubscription(TestingCommons.multistream(up3) as GenericMultistream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
         then:
         ethereumSubscribe3.getAvailableTopics().toSet() == [EthereumEgressSubscription.METHOD_LOGS, EthereumEgressSubscription.METHOD_NEW_HEADS, EthereumEgressSubscription.METHOD_PENDING_TXES].toSet()
+        when:
+        def up4 = TestingCommons.upstream(TestingCommons.api(), "eth_getBlockByNumber")
+        up4.getConnectorMock().setLiveness(Flux.just(true))
+        up4.stop()
+        up4.start()
+        def ethereumSubscribe4 = new EthereumEgressSubscription(TestingCommons.multistream(up4) as GenericMultistream, Schedulers.boundedElastic(), null)
+        then:
+        ethereumSubscribe4.getAvailableTopics().toSet() == [EthereumEgressSubscription.METHOD_NEW_HEADS].toSet()
 
     }
 }