azure_snitch: Do nothing on non-io-cpu

All snitch drivers are supposed to snitch info on some shard and
replicate the dc/rack info across others. All, but azure really do so.
The azure one gets dc/rack on all shards, which's excessive but not
terrible, but when all shards start to replicate their data to all the
others, this may lead to use-after-frees.

fixes: #10494

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>

locator/azure_snitch.cc

@@ -31,6 +31,10 @@ azure_snitch::azure_snitch(const snitch_config& cfg) : production_snitch_base(cf
 }
 
 future<> azure_snitch::load_config() {
+    if (this_shard_id() != io_cpu_id()) {
+        co_return;
+    }
+
     sstring region = co_await azure_api_call(REGION_NAME_QUERY_PATH);
     sstring azure_zone = co_await azure_api_call(ZONE_NAME_QUERY_PATH);