Change the tree name to mysql-5.1-innodb in .bzr-mysql/default.conf

.bzr-mysql/default.conf

 [MYSQL]
 post_commit_to = "commits@lists.mysql.com"
 post_push_to = "commits@lists.mysql.com"
-tree_name = "mysql-5.1"
+tree_name = "mysql-5.1-innodb"