Fixed postgresql_db failing on Python 2.4 with --check

This reverts commit 81cbdb6c8c and adds ignoring of the SystemExit exception because of Python 2.4.

database/postgresql/postgresql_db.py

@@ -281,7 +281,8 @@ def main():
             elif state == "present":
                 changed = not db_matches(cursor, db, owner, template, encoding,
                                          lc_collate, lc_ctype)
-        else:
+            module.exit_json(changed=changed,db=db)
+
         if state == "absent":
             changed = db_delete(cursor, db)
 
@@ -290,6 +291,9 @@ def main():
                                 lc_collate, lc_ctype)
     except NotSupportedError, e:
         module.fail_json(msg=str(e))
+    except SystemExit:
+        # Avoid catching this on Python 2.4 
+        raise
     except Exception, e:
         module.fail_json(msg="Database query failed: %s" % e)