gossip: Fix tokens assignment in assassinate_endpoint

The tokens vector is defined a few lines above and is needed outsie the
if block.

Do not redefine it again in the if block, otherwise the tokens will be empty.

Found by code inspection.

Fixes #3551.

Message-Id: <c7a06375c65c950e94236571127f533e5a60cbfd.1530002177.git.asias@scylladb.com>
(cherry picked from commit c3b5a2ecd5)

gms/gossiper.cc

@@ -984,7 +984,7 @@ future<> gossiper::assassinate_endpoint(sstring address) {
             logger.warn("Assassinating {} via gossip", endpoint);
             if (es) {
                 auto& ss = service::get_local_storage_service();
-                auto tokens = ss.get_token_metadata().get_tokens(endpoint);
+                tokens = ss.get_token_metadata().get_tokens(endpoint);
                 if (tokens.empty()) {
                     logger.warn("Unable to calculate tokens for {}.  Will use a random one", address);
                     throw std::runtime_error(sprint("Unable to calculate tokens for %s", endpoint));

locator/ec2_multi_region_snitch.cc

@@ -100,7 +100,6 @@ future<> ec2_multi_region_snitch::gossiper_starting() {
     // Note: currently gossiper "main" instance always runs on CPU0 therefore
     // this function will be executed on CPU0 only.
     //
-    ec2_snitch::gossiper_starting();
 
     using namespace gms;
     auto& g = get_local_gossiper();