Revert "Additional log on plug-in self-registration and failures."

This reverts commit c0732b1301


The commit broke server startup with:

java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
        at com.google.gerrit.extensions.registration.DynamicSet.<clinit>(DynamicSet.java:45)
        at com.google.gerrit.server.config.GerritGlobalModule.configure(GerritGlobalModule.java:146

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/registration/DynamicSet.java

@@ -25,9 +25,6 @@ import com.google.inject.name.Named;
 import com.google.inject.util.Providers;
 import com.google.inject.util.Types;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.NoSuchElementException;
@@ -42,7 +39,6 @@ import java.util.concurrent.atomic.AtomicReference;
  * registrations to decide between singleton and non-singleton members.
  */
 public class DynamicSet<T> implements Iterable<T> {
-  private static final Logger log = LoggerFactory.getLogger(DynamicSet.class);
   /**
    * Declare a singleton {@code DynamicSet<T>} with a binder.
    * <p>
@@ -151,8 +147,7 @@ public class DynamicSet<T> implements Iterable<T> {
             try {
               next = p.get();
             } catch (RuntimeException e) {
-              log.error("Cannot get iterated object from provider " + p
-                  + ": object discared", e);
+              // TODO Log failed member of DynamicSet.
             }
           }
         }