Revert "redisBufferRead: Clear REDIS_CONNECTED flag when server closed connection"
Revert "redisBufferRead: Clear REDIS_CONNECTED flag when server closed connection"

This reverts commit 1db17f257b1999114c699e77e204f1a91143e5ad.

If the `REDIS_CONNECTED` flag is cleared,
the async onDisconnect callback function will never be called.
This causes problems as the disconnect is never reported back to the user.

Closes #359

redis/hiredis,olgeni/hiredis,thomaslee/hiredis,charsyam/hiredis,hidebug/hiredis,rangan337/hiredis,Yhgenomics/hiredis,jinguoli/hiredis,galdor/hiredis,thomaslee/hiredis,jinguoli/hiredis,redis/hiredis,hidebug/hiredis,owent-contrib/hiredis,owent-contrib/hiredis,Yhgenomics/hiredis,charsyam/hiredis,rangan337/hiredis,galdor/hiredis,jinguoli/hiredis,redis/hiredis,olgeni/hiredis