修复Keeper构建的http保活请求格式错误

platform/src/key_keeper.cpp

@@ -512,8 +512,8 @@ static int health_check(struct key_keeper *keeper)
     	"Host: %s:%d\r\n"
     	"User-Agent: curl/7.47.0\r\n"
     	"Accept: */*\r\n"
-    	"Content-Length: %d\r\n\r\n"
-    	"%s\r\n";
+    	"Content-Length: %d\r\n"
+    	"\r\n%s";
 	sprintf(req_buff, post_head, "/ca?health_check=1", keeper->cert_store_host, keeper->cert_store_port, strlen("health check"), "health check");
 
 	int sockfd = socket(AF_INET, SOCK_STREAM, 0);