Upgrade from 4.0.11 to 4.0.12.

<ChangeLog>

Redis 4.0.12 Released Tue Dec 11 18:06:12 CEST 2018

This backports the following Redis 5 fixes back into Redis 4.
Please check the Redis 5 changelog or see the full commit messages
for more information. Note that there are important fixes to the AOF
implementation so Redis 4.0.12 should be considered as a worthwhile
upgrade in production environments where AOF is used and there is the
idea of sticking with Redis 4 for some time.

b6cd3b3c asyncCloseClientOnOutputBufferLimitReached(): don't free fake clients.
e16402b0 Don't call sdscmp() with shared.maxstring or shared.minstring
49d9f411 Fix stringmatchlen() read past buffer bug.
97192e2d Merge pull request #5569 from maximebedard/backport-4497
1908aba7 add linkClient(): adds the client and caches the list node.
239b0857 networking: optimize unlinkClient() in freeClient()
54b17f98 When replica kills a pending RDB save during SYNC, log it.
b31c08db Move child termination to readSyncBulkPayload
21971ac8 Prevent RDB autosave from overwriting full resync results
3a91fcbc aof.c: improve indentation and change warning message.
e6f287d5 AOF: discard if we lost EXEC when loading aof
e0d4c66a Fix AOF comment to report the current behavior.

</ChangeLog>