TasksStorage: Remove synchronized from methods

These aren't expected to be necessary for correctness.

Change-Id: Id23d3b385e289ba453638b76d6523016a5aabf2a
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java b/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java
index 0d5604c..c847f55 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java
@@ -137,11 +137,11 @@
     return isMultiPrimary;
   }
 
-  public synchronized String create(ReplicateRefUpdate r) {
+  public String create(ReplicateRefUpdate r) {
     return new Task(r).create();
   }
 
-  public synchronized Set<String> start(UriUpdates uriUpdates) {
+  public Set<String> start(UriUpdates uriUpdates) {
     Set<String> startedRefs = new HashSet<>();
     for (ReplicateRefUpdate update : uriUpdates.getReplicateRefUpdates()) {
       Task t = new Task(update);
@@ -152,13 +152,13 @@
     return startedRefs;
   }
 
-  public synchronized void reset(UriUpdates uriUpdates) {
+  public void reset(UriUpdates uriUpdates) {
     for (ReplicateRefUpdate update : uriUpdates.getReplicateRefUpdates()) {
       new Task(update).reset();
     }
   }
 
-  public synchronized void recoverAll() {
+  public void recoverAll() {
     streamRunning().forEach(r -> new Task(r).recover());
   }