anetPeerToString(): make unix sockets distinguishable.

Following the CLIENT LIST output format, we prefix the unix socket
address with a "/" so that it is different than an IPv4/6 address.
This makes parsing simpler.

Related to #2010.
Fix hiredis getaddrinfo leak

Fixed in Redis by 1a5e5b6, but since that part of code
is largely copy/paste from Redis, the fix needs to be
ported over too.

Closes #2012
Merge pull request #2014 from mattsta/fix-hiredis-leak

Fix hiredis getaddrinfo leak
First version of release scripts.
02_upload_tarball.sh fixes.
03_release_hash.sh: fix commit stage.
Quick, wrong, fix for create_tarball script.
03_release_hahs.sh: let me edit before committing.
Fix 03_release_hash.sh commit message.
Linenoise lib updated.
DEBUG POPULATE two args form implemented.

The old DEBUG POPULATE form for automatic creation of test keys is:

    DEBUG POPULATE <count>

Now an additional form is available:

    DEBUG POPULATE <count> <prefix>

When prefix is not specified, it defaults to "key", so the keys are
named incrementally from key:0 to key:<count-1>. Otherwise the specified
prefix is used instead of "key".

The command is useful in order to populate different Redis instances
with key names guaranteed to don't collide. There are other debugging
uses, for example it is possible to add additional N keys using a count
of N and a random prefix at every call.
Improve disable save comment in redis.conf

Closes #1897
Remove surplus double quotes

Closes #1877
Update linenoise accessory files

The core linenoise code was being backported, but not
the README or example.  It's less confusing for users
if everything matches across directories.

Fix inspired by @thrig

Closes #1872
Fix many small typos

Closes #1871
Fix incorrect comments

error != success; and 0 != number of bytes written

Closes #1806
Fix typo in redis.conf

Closes #1713
Fix typo

Closes #1682
Fix typo in 00-RELEASENOTES

Closes #1673
Fix typo

Closes #1544