Invalid apcu.serializer value

[adamfranco]

(Same issue as webtatic-rpms/php71w#7)

This package includes an invalid value for apcu.serializer:

; Defines which serializer should be used. Default is the standard PHP serializer.
apc.serializer='default'

Which should be:

; Defines which serializer should be used. Default is the standard PHP serializer.
apc.serializer=php

The upstream issue is krakjoe/apcu#260 -- the official documentation had the wrong value listed as the default, which should be php.

I noticed this as the /etc/php.d/apcu.ini installed by this package was causing segfaults in PHP7.1 in some cases when apc_cache_clear() and apcu_fetch() were called. Using apc.serializer=php does not have the same issue. I don't have a PHP7.2 setup installed to test, but webtatic-rpms/php70w#1 has a test script.