Use own Nullable instead of javax.annotation.Nullable.

Since d6ccccf96a238 Gerrit uses own Nullable annotation type and the jsr305
library was removed as it was not needed any more after that.

Change-Id: Id7639bca1c1e924fc98bfdb0028754bd6c0de0fd

src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java b/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
index 523c5b6..4cdf04a 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
@@ -18,8 +18,6 @@
 import java.util.Collections;
 import java.util.List;
 
-import javax.annotation.Nullable;
-
 import org.eclipse.jgit.api.errors.ConcurrentRefUpdateException;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
 import org.eclipse.jgit.errors.MissingObjectException;
@@ -37,6 +35,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.common.data.LabelType;
 import com.google.gerrit.common.data.LabelTypes;
 import com.google.gerrit.reviewdb.client.Change;