I originally added escapeqq as part of 75c03368 (zodbdump: Start to
stabilize output format) with the task for this utility to quote string
into valid "..." string always quoted with ".

This utility was later copied to pygolang:

	pygolang@afa46cf5

and then further improved there to work under both Python2 and Python3
and to not escape printable UTF-8 characters:

	pygolang@02dddb97

So stop the duplication and simply switch to the better version.