Test: dump.tcl fixed for RESTORE new error msg.
Test: AOF test false positive when running in slow hosts.

The bug was triggered by running the test with Valgrind (which is a lot
slower and more sensible to timing issues) after the recent changes
that made Redis more promptly able to reply with the -LOADING error.
Cluster: slave validity factor is now user configurable.

Check the commit changes in the example redis.conf for more information.
Tag every log line with role.

Every log contains, just after the pid, a single character that provides
information about the role of an instance:

S - Slave
M - Master
C - Writing child
X - Sentinel
redisLogFromHandler() format changed to match new logs format.