PluginDaemonTest: Expose plugin name

Plugin tests have to know plugin name. Change the modifier for the
existing pluginName variable from private to protected.

Change-Id: I9876cb1c800d60eecb7166655d5d34a0784f2a64

gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/PluginDaemonTest.java

diff --git a/gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/PluginDaemonTest.java b/gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/PluginDaemonTest.java
index c71e13f..dde1875 100644
--- a/gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/PluginDaemonTest.java
+++ b/gerrit-acceptance-framework/src/test/java/com/google/gerrit/acceptance/PluginDaemonTest.java
@@ -48,9 +48,9 @@
   private Path pluginsSitePath;
   private Path pluginSubPath;
   private Path pluginSource;
-  private String pluginName;
   private boolean standalone;
 
+  protected String pluginName;
   protected Path testSite;
 
   @Override