MDL-63292 tool_policy: Increment version of the merged plugin

This is to distinguish the versions available from the plugins directory
from the versions that are part of Moodle standard distribution.

admin/tool/policy/version.php

@@ -24,6 +24,6 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version = 2017051519;
+$plugin->version = 2017051550;
 $plugin->requires = 2017051505;        // Moodle 3.3.5 (Build: 20180319) and upwards.
 $plugin->component = 'tool_policy';