Merge changes I5574623f,Iffbea430

* changes:
  Test that check cannot be created for invalid checker
  Disallow creation of checks for non-existing checkers
diff --git a/java/com/google/gerrit/plugins/checks/Checkers.java b/java/com/google/gerrit/plugins/checks/Checkers.java
index a50a875..9c00528 100644
--- a/java/com/google/gerrit/plugins/checks/Checkers.java
+++ b/java/com/google/gerrit/plugins/checks/Checkers.java
@@ -82,7 +82,6 @@
    * @return the checkers that apply that apply to the given repository, sorted by UUID
    * @throws IOException if reading the checker list fails or if any checker couldn't be retrieved
    *     from the storage
-   * @throws ConfigInvalidException if reading the checker list fails
    */
   ImmutableSortedSet<Checker> checkersOf(Project.NameKey repositoryName) throws IOException;
 }
diff --git a/java/com/google/gerrit/plugins/checks/api/HttpModule.java b/java/com/google/gerrit/plugins/checks/api/HttpModule.java
index f48ec72..21ab47f 100644
--- a/java/com/google/gerrit/plugins/checks/api/HttpModule.java
+++ b/java/com/google/gerrit/plugins/checks/api/HttpModule.java
@@ -14,7 +14,6 @@
 
 package com.google.gerrit.plugins.checks.api;
 
-import com.google.gerrit.extensions.restapi.RestApiModule;
 import com.google.inject.servlet.ServletModule;
 
 public class HttpModule extends ServletModule {
@@ -22,14 +21,5 @@
   @Override
   protected void configureServlets() {
     serveRegex("^/checkers/(.*)$").with(CheckersRestApiServlet.class);
-
-    install(
-        new RestApiModule() {
-          @Override
-          public void configure() {
-            // Checkers
-
-          }
-        });
   }
 }
diff --git a/java/com/google/gerrit/plugins/checks/db/CheckerConfig.java b/java/com/google/gerrit/plugins/checks/db/CheckerConfig.java
index 66257e8..c5891a6 100644
--- a/java/com/google/gerrit/plugins/checks/db/CheckerConfig.java
+++ b/java/com/google/gerrit/plugins/checks/db/CheckerConfig.java
@@ -63,9 +63,9 @@
  * <h2>Internal details</h2>
  *
  * <p>Each checker is represented by a commit on a branch as defined by {@link
- * CheckerRef#refsCheckers(CheckerUuid)}. Previous versions of the checker exist as older commits on
- * the same branch and can be reached by following along the parent references. New commits for
- * updates are only created if a real modification occurs.
+ * CheckerUuid#toRefName()}. Previous versions of the checker exist as older commits on the same
+ * branch and can be reached by following along the parent references. New commits for updates are
+ * only created if a real modification occurs.
  *
  * <p>Within each commit, the properties of a checker are stored in <em>checker.config</em> file
  * (further specified by {@link CheckerConfigEntry}). The <em>checker.config</em> file is formatted