proxy RFC4525 increment; bail out in case of unsupported extension (ITS#5912)

servers/slapd/back-ldap/init.c

@@ -62,7 +62,10 @@ ldap_back_initialize( BackendInfo *bi )
 		 * and the entryTtl attribute */
 		SLAP_BFLAG_DYNAMIC |
 #endif /* LDAP_DYNAMIC_OBJECTS */
-		0;
+
+		/* back-ldap recognizes RFC4525 increment;
+		 * let the remote server complain, if needed (ITS#5912) */
+		SLAP_BFLAG_INCREMENT;
 
 	bi->bi_open = ldap_back_open;
 	bi->bi_config = 0;

servers/slapd/back-meta/init.c

@@ -53,7 +53,10 @@ meta_back_initialize(
 		SLAP_BFLAG_DYNAMIC |
 #endif /* LDAP_DYNAMIC_OBJECTS */
 #endif
-		0;
+
+		/* back-meta recognizes RFC4525 increment;
+		 * let the remote server complain, if needed (ITS#5912) */
+		SLAP_BFLAG_INCREMENT;
 
 	bi->bi_open = meta_back_open;
 	bi->bi_config = 0;

servers/slapd/modify.c

@@ -268,6 +268,7 @@ fe_op_modify( Operation *op, SlapReply *rs )
 	if ( op->orm_increment && !SLAP_INCREMENT( op->o_bd ) ) {
 		send_ldap_error( op, rs, LDAP_UNWILLING_TO_PERFORM,
 			"modify/increment not supported in context" );
+		goto cleanup;
 	}
 
 	/*