doc: Document HDD_LEAVE_SPACE_DEFAULT chunkserver parameter

 Thanks, Marcin Sulikowski.

Signed-off-by: Dmitry Smirnov <onlyjob@member.fsf.org>
doc: Don't use word "metadata" in chunkserver config.

Signed-off-by: Dmitry Smirnov <onlyjob@member.fsf.org>
doc: Correct MASTER_RECONNECTION_DELAY timeout

Signed-off-by: Dmitry Smirnov <onlyjob@member.fsf.org>
doc: Correct MASTER port number

Signed-off-by: Dmitry Smirnov <onlyjob@member.fsf.org>
master: Updated MASTER_RECONNECTION_DELAY

Signed-off-by: Dmitry Smirnov <onlyjob@member.fsf.org>