BUG/MINOR: proxy: fix check_{command,path} leak on deinit()

proxy check_{command,path} members (used for "external-check" feature)
weren't cleaned up in free_proxy(), resulting in small memory leak if
"external-check command" or "external-check path" were used on a regular
or default proxy.

It may be backported to all stable versions.

(cherry picked from commit 62d0465a96ac847f40e95a9474d8971dac062114)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 7680c52b16ab9a6b2f55430ee3a0eb3eac904eb2)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 0e726651301572dd21006fe2892ac658eee71fdd)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/proxy.c b/src/proxy.c
index 71322b6..511884f 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -172,6 +172,8 @@
 	free(p->capture_name);
 	istfree(&p->monitor_uri);
 	istfree(&p->server_id_hdr_name);
+	ha_free(&p->check_command);
+	ha_free(&p->check_path);
 	free(p->rdp_cookie_name);
 	free(p->invalid_rep);
 	free(p->invalid_req);