SENTRY-2469: Fix bugs in RoleServlet (Hongtaq Zhao reviewed by Arjun Mishra)

Change-Id: I87fbb2e1cd1bb6cc22c93a2069316f9701b6ea26
diff --git a/sentry-service/sentry-service-server/src/main/java/org/apache/sentry/api/service/thrift/RolesServlet.java b/sentry-service/sentry-service-server/src/main/java/org/apache/sentry/api/service/thrift/RolesServlet.java
index 9ed2bf3..aea7455 100644
--- a/sentry-service/sentry-service-server/src/main/java/org/apache/sentry/api/service/thrift/RolesServlet.java
+++ b/sentry-service/sentry-service-server/src/main/java/org/apache/sentry/api/service/thrift/RolesServlet.java
@@ -59,6 +59,8 @@
     } catch (Exception e) {
       response.sendError(HttpServletResponse.SC_BAD_REQUEST, e.getMessage());
     }
+    finally {
     out.close();
+    }
   }
 }