Fix creation of missing repository when replicating to a Gerrit server

When replicating to a Gerrit server over http, non-existence of a
repository is reported as:

  <repo-name> unavailable

This message wasn't among expected messages and creation of the missing
repository wasn't executed.

Bug: Issue 11204
Change-Id: I3d6c3e14573b638b17d54d1777a606b8f356f1f9
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
index 9fe497b..5f0c066 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
@@ -343,7 +343,8 @@
       String msg = e.getMessage();
       if (msg.contains("access denied")
           || msg.contains("no such repository")
-          || msg.contains("Git repository not found")) {
+          || msg.contains("Git repository not found")
+          || msg.contains("unavailable")) {
         createRepository();
       } else {
         repLog.error("Cannot replicate {}; Remote repository error: {}", projectName, msg);