[BUG] uri_auth: do not attemp to convert uri_auth -> http-request more than once

Bug reported by Laurent Dolosor.
diff --git a/include/common/uri_auth.h b/include/common/uri_auth.h
index a73c1ad..bffd694 100644
--- a/include/common/uri_auth.h
+++ b/include/common/uri_auth.h
@@ -30,6 +30,7 @@
 #define	ST_SHNODE	0x00000002	/* show node name */
 #define	ST_SHDESC	0x00000004	/* show description */
 #define	ST_SHLGNDS	0x00000008	/* show legends */
+#define	ST_CONVDONE	0x00000010	/* req_acl conversion done */
 
 /* later we may link them to support multiple URI matching */
 struct uri_auth {
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 90cc9b0..b5437a6 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -4803,7 +4803,8 @@
 			}
 		}
 
-		if (curproxy->uri_auth && !LIST_ISEMPTY(&curproxy->uri_auth->req_acl) &&
+		if (curproxy->uri_auth && !(curproxy->uri_auth->flags & ST_CONVDONE) &&
+		    !LIST_ISEMPTY(&curproxy->uri_auth->req_acl) &&
 		    (curproxy->uri_auth->userlist || curproxy->uri_auth->auth_realm )) {
 			Alert("%s '%s': stats 'auth'/'realm' and 'http-request' can't be used at the same time.\n",
 			      "proxy", curproxy->id);
@@ -4811,7 +4812,7 @@
 			goto out_uri_auth_compat;
 		}
 
-		if (curproxy->uri_auth && curproxy->uri_auth->userlist) {
+		if (curproxy->uri_auth && curproxy->uri_auth->userlist && !(curproxy->uri_auth->flags & ST_CONVDONE)) {
 			const char *uri_auth_compat_req[10];
 			struct req_acl_rule *req_acl;
 			int i = 0;
@@ -4842,6 +4843,8 @@
 				free(curproxy->uri_auth->auth_realm);
 				curproxy->uri_auth->auth_realm = NULL;
 			}
+
+			curproxy->uri_auth->flags |= ST_CONVDONE;
 		}
 out_uri_auth_compat: