Attempt to prevent false positives in replication test.
Fix lua-cmsgpack 64 bit integer on 32 bit platform

This syncs lua-cmsgpack with the mattsta/lua-cmsgpack upstream.

Fixes #2161
Merge pull request #2162 from mattsta/fix/lua/cmsgpack/64-bit-integers-on-32-bit-platforms

Fix lua-cmsgpack 64 bit integer on 32 bit platform
Avoid valgrind memory leak false positive in processInlineBuffer().

zmalloc(0) cauesd to actually trigger a non-zero allocation since with
standard libc malloc we have our own zmalloc header for memory tracking,
but at the same time the returned pointer is at the end of the block and
not in the middle. This triggers a false positive when testing with
valgrind.

When the inline protocol args count is 0, we now avoid reallocating
c->argv, preventing the issue to happen.
Merge remote-tracking branch 'origin/unstable' into unstable
Document redis-cli --stat in --help output.
Fix DEBUG OBJECT lru field to report seconds.

Because of (not so) recent Redis changes, now the LRU internally
reported unit is milliseconds, not seconds, but the DEBUG OBJECT output
was still claiming seconds while providing milliseconds.
However OBJECT IDLETIME was working as expected, which is the correct
API to use.