A filter handle is returned and can be used to unregister a filter.  In
the future it can also be used to further configure or manipulate the
filter.

Filters are now automatically unregistered when a module unloads.

in diskless replication - master was not notifing the slave that rdb transfer
terminated on error, and lets slave wait for replication timeout

Related to #3829.

See #3829.

also reduce an excess sleep

this is very confusing to see the server disappears as if it got SIGKILL when it was not the case.

Enlarge error buffer in redis-check-aof.c to remove compiler warning of output truncation through snprintf format string

Hi, @antirez

In the code, to get the size of ziplist, "unsigned int bytes = ZIPLIST_HEADER_SIZE+1;" is correct, 
but why not make it more readable and easy to understand

removed obsolete warning as per - https://github.com/antirez/redis/is…

when redis appends the blocked client reply list to the real client, it didn't
bother to check if it is in fact the master client. so a slave executing that
module command will send replies to the master, causing the master to send the
slave error responses, which will mess up the replication offset
(slave will advance it's replication offset, and the master does not)

On `make uninstall`, removes:

- /usr/local/bin/redis-benchmark
- /usr/local/bin/redis-check-aof
- /usr/local/bin/redis-check-rdb
- /usr/local/bin/redis-cli
- /usr/local/bin/redis-sentinel
- /usr/local/bin/redis-server

(Only the src/ versions are removed in `make clean`)

Bug signaled by @vattezhang in PR #5940 but fixed differently.