Fix clients timeout handling.

During the refactoring of blocking operations, commit
82b672f6335ac2db32a724ba5dc10398c949a4a8, a bug was introduced where
a milliseconds time is compared to a seconds time, so all the clients
always appear to timeout if timeout is set to non-zero value.

Thanks to Jonathan Leibiusky for finding the bug and helping verifying
the cause and fix.
Fixed typos in redis.conf file.
Fixed grammar: before H the article is a, not an.
Fixed grammar: 'usually' to 'usual'
Merge pull request #1437 from AnuragRamdasan/patch-1

Fixed grammar: 'usually' to 'usual'
fixed typo
Merge pull request #1438 from AnuragRamdasan/patch-2

fixed typo
Grammar fix.
Merge pull request #1439 from AnuragRamdasan/patch-3

Grammar fix.
Fixed typo in redis.conf.
Sentinel: fix reported role fields when master is reset.

When there is a master address switch, the reported role must be set to
master so that we have a chance to re-sample the INFO output to check if
the new address is reporting the right role.

Otherwise if the role was wrong, it will be sensed as wrong even after
the address switch, and for enough time according to the role change
time, for Sentinel consider the master SDOWN.

This fixes isue #1446, that describes the effects of this bug in
practice.
Sentinel: fix reported role info sampling.

The way the role change was recoded was not sane and too much
convoluted, causing the role information to be not always updated.

This commit fixes issue #1445.