database: update schema version

Problem: The schema version of the flux-accounting database was never
updated with the addition of the jobs table in #357.

Update the schema version number of the flux-accounting database.

src/bindings/python/fluxacct/accounting/__init__.py.in

@@ -1,5 +1,5 @@
 db_dir = "@X_LOCALSTATEDIR@/lib/flux/"
 db_path = "@X_LOCALSTATEDIR@/lib/flux/FluxAccounting.db"
-db_schema_version = 21
+db_schema_version = 22
 
 __all__ = ["db_dir", "db_path", "db_schema_version"]