Use DB_REPLICA instead of DB_SLAVE on MW1.34

[RhinosF1]

Stack Trace

2019-11-01 16:09:11 test1 test1wiki: [7cae80582ed36dce26eb4adb] /wiki/Special:RecentChanges UnexpectedValueException from line 462 of /srv/mediawiki/w/includes/libs/rdbms/loadbalancer/LoadBalancer.php: Invalid server index index #DB_SLAVE
#0 /srv/mediawiki/w/includes/libs/rdbms/loadbalancer/LoadBalancer.php(896): Wikimedia\Rdbms\LoadBalancer->getConnectionIndex(string, array, string)
#1 /srv/mediawiki/w/includes/libs/rdbms/loadbalancer/LoadBalancer.php(1043): Wikimedia\Rdbms\LoadBalancer->getConnection(string, array, string, integer)
#2 /srv/mediawiki/w/includes/GlobalFunctions.php(2576): Wikimedia\Rdbms\LoadBalancer->getMaintenanceConnectionRef(string, array, string)
#3 /srv/mediawiki/w/extensions/RecentChangesLogFilter/RecentChangesLogFilter.hooks.php(49): wfGetDB(string)
#4 /srv/mediawiki/w/includes/Hooks.php(174): RecentChangesLogFilterHooks::onChangesListSpecialPageQuery(string, array, array, array, array, array, FormOptions)
#5 /srv/mediawiki/w/includes/Hooks.php(202): Hooks::callHook(string, array, array, NULL)
#6 /srv/mediawiki/w/includes/specialpage/ChangesListSpecialPage.php(1625): Hooks::run(string, array)
#7 /srv/mediawiki/w/includes/specials/SpecialRecentChanges.php(313): ChangesListSpecialPage->runMainQueryHook(array, array, array, array, array, FormOptions)
#8 /srv/mediawiki/w/includes/specialpage/ChangesListSpecialPage.php(1023): SpecialRecentChanges->doMainQuery(array, array, array, array, array, FormOptions)
#9 /srv/mediawiki/w/includes/specialpage/ChangesListSpecialPage.php(629): ChangesListSpecialPage->getRows()
#10 /srv/mediawiki/w/includes/specials/SpecialRecentChanges.php(165): ChangesListSpecialPage->execute(NULL)
#11 /srv/mediawiki/w/includes/specialpage/SpecialPage.php(575): SpecialRecentChanges->execute(NULL)
#12 /srv/mediawiki/w/includes/specialpage/SpecialPageFactory.php(611): SpecialPage->run(NULL)
#13 /srv/mediawiki/w/includes/MediaWiki.php(296): MediaWiki\Special\SpecialPageFactory->executePath(Title, RequestContext)
#14 /srv/mediawiki/w/includes/MediaWiki.php(900): MediaWiki->performRequest()
#15 /srv/mediawiki/w/includes/MediaWiki.php(527): MediaWiki->main()
#16 /srv/mediawiki/w/index.php(44): MediaWiki->run()
#17 {main}

MW Changelog
The constant DB_SLAVE, deprecated in 1.28, has been removed. Use DB_REPLICA.