Clean only floating-ip related connection states

Clean only floating-ip related connection states

Currently init_l3 deletes connection states related to ALL ips deleted
in init_l3 but it's required only when floating-ips are deleted[1].

This change deletes only connection states related to floating-ips
deleted in init_l3 ... it avoids to delete connection states in dhcp
agents and on router internal ports!

[1] look at change Ia9bd7ae243a0859dcb97e2fa939f7d16f9c2456c

Closes-Bug: #1452434
Related-Bug: #1334926
Change-Id: Icfcfc585df6fd41de1e1345fd731e4631a6950ce