[HookTask] Avoid shadowing field

Rename local variable to avoid shadowing field declared in line 42.

Change-Id: Ic7cdfe55aca4e7072d3c4e26928d3b4f98bb8457
diff --git a/src/main/java/com/googlesource/gerrit/plugins/hooks/HookTask.java b/src/main/java/com/googlesource/gerrit/plugins/hooks/HookTask.java
index 76de6e3..b6654da 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/hooks/HookTask.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/hooks/HookTask.java
@@ -107,9 +107,9 @@
 
       ps = pb.start();
       ps.getOutputStream().close();
-      String output = new String(ByteStreams.toByteArray(ps.getInputStream()), UTF_8);
+      String out = new String(ByteStreams.toByteArray(ps.getInputStream()), UTF_8);
       ps.waitFor();
-      result = new HookResult(ps.exitValue(), output);
+      result = new HookResult(ps.exitValue(), out);
     } catch (InterruptedException iex) {
       // InterruptedException - timeout or cancel
       args.metrics.timeout(name);