switch an occurence of GROUP_ROLES to GROUP_ROLE, a=chris

diff --git a/lib/upgrade_functions.php b/lib/upgrade_functions.php
index 53e22ee3e..c51626873 100644
--- a/lib/upgrade_functions.php
+++ b/lib/upgrade_functions.php
@@ -544,9 +544,9 @@ function upgradeDatabaseVersion17(&$db)
     $db->execute("CREATE TABLE GROUPS (GROUP_ID INTEGER PRIMARY KEY
         $auto_increment ,GROUP_NAME VARCHAR(128), CREATED_TIME INT(11),
            CREATOR_ID INT(11))");
-    $db->execute("CREATE TABLE USER_GROUPS (USER_ID INTEGER ,
+    $db->execute("CREATE TABLE USER_GROUP (USER_ID INTEGER ,
         GROUP_ID INTEGER,PRIMARY KEY (GROUP_ID, USER_ID) )");
-    $db->execute("CREATE TABLE GROUP_ROLES (GROUP_ID INTEGER ,
+    $db->execute("CREATE TABLE GROUP_ROLE (GROUP_ID INTEGER ,
         ROLE_ID INTEGER)");

     addActivityAtId($db, 'db_activity_manage_groups', "manageGroups", 4);