MDL-29029 move health center to admin tools

AMOS BEGIN
 MOV [healthcenter,moodle],[pluginname,tool_health]
 MOV [healthnoproblemsfound,moodle],[healthnoproblemsfound,tool_health]
 MOV [healthproblemsdetected,moodle],[healthproblemsdetected,tool_health]
 MOV [healthproblemsolution,moodle],[healthproblemsolution,tool_health]
 MOV [healthreturntomain,moodle],[healthreturntomain,tool_health]
 MOV [healthsolution,moodle],[healthsolution,tool_health]
AMOS END

lib/pluginlib.php

@@ -367,7 +367,8 @@ class plugin_manager {
             ),
 
             'tool' => array(
-                'bloglevelupgrade', 'capability', 'generator', 'profiling', 'unittest', 'unsuproles'
+                'bloglevelupgrade', 'capability', 'generator', 'health',
+                'profiling', 'unittest', 'unsuproles'
             ),
 
             'webservice' => array(