Add ApiArgValidator import to GetUserCmd.java

Author: daviftorres

api/src/main/java/org/apache/cloudstack/api/command/admin/user/GetUserCmd.java

@@ -22,7 +22,7 @@
 import org.apache.cloudstack.api.BaseCmd;
 import org.apache.cloudstack.api.Parameter;
 import org.apache.cloudstack.api.response.UserResponse;
-
+import org.apache.cloudstack.api.ApiArgValidator;
 import com.cloud.exception.InvalidParameterValueException;
 import com.cloud.user.UserAccount;