AbstractCheckersTest: Adjust to changed package of HttpModule

The HttpModule class was moved from the api package to the root
package in change If47336c51, but the package was not adjusted in
the @TestPlugin statement in AbstractCheckersTest.

Change-Id: I910c8a2c831317e9aeff7fcbc024571cee7f8343
diff --git a/java/com/google/gerrit/plugins/checks/acceptance/AbstractCheckersTest.java b/java/com/google/gerrit/plugins/checks/acceptance/AbstractCheckersTest.java
index 1fa9f2d..de02574 100644
--- a/java/com/google/gerrit/plugins/checks/acceptance/AbstractCheckersTest.java
+++ b/java/com/google/gerrit/plugins/checks/acceptance/AbstractCheckersTest.java
@@ -32,7 +32,7 @@
 @TestPlugin(
     name = "checks",
     sysModule = "com.google.gerrit.plugins.checks.acceptance.TestModule",
-    httpModule = "com.google.gerrit.plugins.checks.api.HttpModule")
+    httpModule = "com.google.gerrit.plugins.checks.HttpModule")
 public class AbstractCheckersTest extends LightweightPluginDaemonTest {
   protected CheckerOperations checkerOperations;
   protected CheckOperations checkOperations;