db_connectinfo overwritten on View objects

[dbarnett]

If you do:

client.db_connectinfo = "DEFAULT_URL"

class CustomView(client.View):
    db_connectinfo = "CUSTOM_URL"

CustomView.execute(...)

and don't explicitly pass a db_connectinfo into execute, execute tries to connect to "DEFAULT_URL".

This is because the 2nd line of execute unconditionally overwrites db_connectinfo on the View instance, setting it to None in this case.