Fix 'Statement unnecessarily nested within else clause' warnings

Change-Id: I53c039d2d8904f6465a5560d9cbb2716df5c48c7

src/main/java/com/googlesource/gerrit/plugins/download/command/GitDownloadCommand.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/download/command/GitDownloadCommand.java b/src/main/java/com/googlesource/gerrit/plugins/download/command/GitDownloadCommand.java
index 8700262..03b817d 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/download/command/GitDownloadCommand.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/download/command/GitDownloadCommand.java
@@ -109,14 +109,12 @@
         ObjectId id = repo.resolve(ref);
         if (id != null) {
           return id.name();
-        } else {
-          log.error(String.format("Cannot resolve ref %s in project %s.", ref,
-              project));
-          return null;
         }
-      } else {
-        return ref;
+        log.error(String.format("Cannot resolve ref %s in project %s.", ref,
+            project));
+        return null;
       }
+      return ref;
     } catch (RepositoryNotFoundException e) {
       log.error(String.format("Missing project: %s",  project), e);
       return null;