#2276 imm: Update NO_DANGLING document with information about ATTR_DN

[Hung Nguyen]

From README.NO_DANGLING:

This flag can only be set for attribute definitions where the attribute data
type is SaNameT and the attribute is a CONFIG attribute.

SaStringT API has been introduced in [#643]. We now can also use NO_DANGLING flag with SaStringT attributes that have DN flag.
The NO_DANGLING document needs to be updated.

[Hung Nguyen]

default (5.2) [staging:38f9e7]
changeset: 8571:38f9e7f6ec5b
user: Hung Nguyen hung.d.nguyen@dektech.com.au
date: Fri Feb 10 16:49:15 2017 +0700
summary: imm: Update NO_DANGLING document with information about ATTR_DN [#2276]

opensaf-5.1.x [staging:c7e402]
changeset: 8572:c7e402c9e46b
user: Hung Nguyen hung.d.nguyen@dektech.com.au
date: Fri Feb 10 16:53:48 2017 +0700
summary: imm: Update NO_DANGLING document with information about ATTR_DN [#2276]

opensaf-5.0.x [staging:ff6122]
changeset: 8573:ff6122ce47a0
user: Hung Nguyen hung.d.nguyen@dektech.com.au
date: Fri Feb 10 16:53:48 2017 +0700
summary: imm: Update NO_DANGLING document with information about ATTR_DN [#2276]