MINOR: proxy: also store the name for a defaults section

There's an optional name, but till now it was not even saved into the
structure, let's keep it.
diff --git a/src/cfgparse-listen.c b/src/cfgparse-listen.c
index 56cab53..3c252d2 100644
--- a/src/cfgparse-listen.c
+++ b/src/cfgparse-listen.c
@@ -261,6 +261,7 @@
 		init_new_proxy(curr_defproxy);
 		proxy_preset_defaults(curr_defproxy);
 		curproxy = curr_defproxy;
+		curproxy->id = strdup(args[1]); // may be empty
 		curproxy->conf.args.file = curproxy->conf.file = strdup(file);
 		curproxy->conf.args.line = curproxy->conf.line = linenum;
 		defproxy.cap = PR_CAP_DEF | PR_CAP_LISTEN; /* all caps for now */
diff --git a/src/proxy.c b/src/proxy.c
index a0aaa5c..5351880 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -1111,6 +1111,7 @@
  */
 void proxy_free_defaults(struct proxy *defproxy)
 {
+	free(defproxy->id); defproxy->id = NULL;
 	free(defproxy->conf.file); defproxy->conf.file = NULL;
 	free(defproxy->check_command); defproxy->check_command = NULL;
 	free(defproxy->check_path); defproxy->check_path = NULL;