Fix DNSLookup memory leak (#422)

* Fix memory leak with shared_ptr and -fsanitize=address

* Replace addrinfo* by shared_ptr

* fsanitize=address only on Linux

* Add USE_WS Linux CI test

* Remove fsanitize from the cmake files

* Remove USE_WS in linux test suite

ws/ws.cpp

@@ -892,9 +892,8 @@ namespace ix
         auto dnsLookup = std::make_shared<DNSLookup>(hostname, 80);
 
         std::string errMsg;
-        struct addrinfo* res;
 
-        res = dnsLookup->resolve(errMsg, [] { return false; });
+        auto res = dnsLookup->resolve(errMsg, [] { return false; });
 
         auto addr = res->ai_addr;