Silence exception when repository is not found

A repository that is not present locally is not to be
considered a severe error, because it is a normal situation
when a new project is created but not yet propagated to
the remote nodes.

Change-Id: I89693d47be117994b6cd6148380b03edb6f2a531

src/main/java/com/googlesource/gerrit/plugins/multisite/validation/ProjectVersionRefUpdate.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/ProjectVersionRefUpdate.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/ProjectVersionRefUpdate.java
index 5171133..84965c0 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/ProjectVersionRefUpdate.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/ProjectVersionRefUpdate.java
@@ -38,6 +38,7 @@
 import java.io.IOException;
 import java.util.Optional;
 import java.util.Set;
+import org.eclipse.jgit.errors.RepositoryNotFoundException;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectIdRef;
 import org.eclipse.jgit.lib.ObjectInserter;
@@ -244,6 +245,8 @@
         logger.atFine().log("Local project '%s' has version %d", projectName, repoVersion);
         return Optional.of(repoVersion);
       }
+    } catch (RepositoryNotFoundException re) {
+      logger.atFine().log("Project '%s' not found", projectName);
     } catch (IOException e) {
       logger.atSevere().withCause(e).log("Cannot read local project '%s' version", projectName);
     }