MDL-22788 upgrade enrol/paypal plugin to use enrolments

Adding file missing from previous commits

enrol/paypal/db/upgrade.php

@@ -0,0 +1,43 @@
+<?php
+
+// This file keeps track of upgrades to
+// the paypal enrolment plugin
+//
+// Sometimes, changes between versions involve
+// alterations to database structures and other
+// major things that may break installations.
+//
+// The upgrade function in this file will attempt
+// to perform all the necessary actions to upgrade
+// your older installation to the current version.
+//
+// If there's something it cannot do itself, it
+// will tell you what you need to do.
+//
+// The commands in here will all be database-neutral,
+// using the methods of database_manager class
+//
+// Please do not forget to use upgrade_set_timeout()
+// before any action that may take longer time to finish.
+
+function xmldb_enrol_paypal_upgrade($oldversion) {
+    global $CFG, $DB, $OUTPUT;
+
+    $dbman = $DB->get_manager();
+
+    // Add instanceid field to enrol_paypal table
+    if ($oldversion < 2010071500) {
+        $table = new xmldb_table('enrol_paypal');
+        $field = new xmldb_field('instanceid');
+        if (!$dbman->field_exists($table, $field)) {
+            $field->set_attributes(XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, 0, 'userid');
+            $dbman->add_field($table, $field);
+        }
+        upgrade_plugin_savepoint(true, 2010071500, 'enrol', 'paypal');
+    }
+
+    //===== 1.9.0 upgrade line ======//
+
+
+    return true;
+}