Switch over to FixedIntervalLoopingCall

LoopingCall has been renamed (without a change) to
FixedIntervalLoopingCall in https://review.openstack.org/#/c/26345/

Adjust to the new name so that the compatibility code can be removed.

Change-Id: I64f62dca5bee580dcd28860760208e9be8f4b659
Closes-Bug: #1307560
netaddr<=0.7.10 raises ValueError instead of AddrFormatError

This patch ensures that ValueError is also caught in addition to
AddrFormatError as in netaddr>=0.7.11 AddrFormatError is raised and
in netaddr<=0.7.10 ValueError is raised.

Change-Id: I595c90e42129a2d365f3860e3042e826bd031365
Closes-bug: #1308675
Merge "Switch over to FixedIntervalLoopingCall"
Merge "netaddr<=0.7.10 raises ValueError instead of AddrFormatError"