Bug 2256:Fixed bug Port cache cleared when network down, making coordinator unreachable

Change-Id: I25991345c2c49151d059eb0de250e6d6da2ab151
Signed-off-by: balakrishnan <balakrishnan.ka@hcl.com>
(cherry picked from commit f544349871f64aac8304c57eeb5ce2741a768531)
Merge "Bug 2256:Fixed bug Port cache cleared when network down, making coordinator unreachable" into stable/helium