healthcheck: handle backported version of ipaddress
healthcheck: handle backported version of ipaddress

When using a backported version of ipaddress for Python 2.x, we must
provide a unicode string, not a byte string. Try to always provide a
unicode string.

blablacar/exabgp,benagricola/exabgp,blablacar/exabgp,benagricola/exabgp,benagricola/exabgp,earies/exabgp,earies/exabgp,blablacar/exabgp,earies/exabgp