Fix memory leak in BgpOListSpec::ToString()
Fix memory leak in BgpOListSpec::ToString()

Allocate temporary BgpOListElem object on stack instead of carving
out the same heap using new operator (and freeing it).

Change-Id: Ia90842f1f7e9f70fc750202c8674367173f8ddc0
Closes-Bug: 1777484

eonpatapon/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller