Fix typo

Author: GabrielBrascher

usage/src/main/java/com/cloud/usage/UsageManagerImpl.java

@@ -289,7 +289,7 @@ public boolean configure(String name, Map<String, Object> params) throws Configu
 
     /**
      * Sets the '_pid' variable based on the cloudstack-usage.service process id (pid) according to the file /var/run/cloudstack-usage.service.pid. </br>
-     * It thorws a CloudRuntimeException in the following cases:
+     * It throws a CloudRuntimeException in the following cases:
      * <ul>
      *  <li>Cannot find the pid file</li>
      *  <li>Cannot read the pid file</li>