storage: fix upgrade when password contains a %

oslo.config doesn't support %{} or %() variable interpolation while
ConfigParser does.

So when a password contains a '%', it's fine for oslo.config
But the Python ConfigParser will raise the exception.

Since alembic use ConfigParser and not oslo.config, we have to escape
the url ourself.

This is not a big deal since, we don't want alembic doing variable
interpolation.

Change-Id: If7bfe7f082f4352fb49992a2216f2dd5b8993711
(cherry picked from commit 268c1e8e9e)

aodh/storage/impl_sqlalchemy.py

@@ -82,7 +82,7 @@ class Connection(base.Connection):
         cfg = config.Config(
             "%s/sqlalchemy/alembic/alembic.ini" % os.path.dirname(__file__))
         cfg.set_main_option('sqlalchemy.url',
-                            self.conf.database.connection)
+                            self.conf.database.connection.replace("%", "%%"))
         return cfg
 
     def upgrade(self, nocreate=False):