LUDOC-270 doc: describe more connect flags

LUDOC-270 doc: describe more connect flags

[2015-06-10, PM]
Clarify OBD_CONNECT_TRUNCLOCK under Mike's guidance.

[2015-06-10]
Andrew did a little editing of Mike's update. OBD_CONNECT_TRUNCLOCK
may still want a some attention.

[201-06-9]
Update document with more details about connection flags

Signed-off-by: Mikhail Pershin <mike.pershin@intel.com>
Change-Id: Ib8369ac6fe009366ad2f4cc16137ebec4874c6ef
Reviewed-on: http://review.whamcloud.com/15191
Tested-by: Jenkins
Reviewed-by: Andrew Uselton <andrew.c.uselton@intel.com>