tcmmd: delete ifb TC before installing the redirection to ifb

When tcmmd's TC rules are active, they are composed of 2 parts:
- a redirection of ingress traffic from eth0 to ifb0 (TC rules installed on
  eth0)
- traffic shapping on ifb0 (TC rules installed on ifb0)

Before tcmmd starts, bad traffic shapping rules on ifb0 might be installed by
other tools. During tcmmd initialisation, redirection to ifb0 was installed
without deleting potential existing rules on ifb0. This patch fixes this.
tests: cleanup ifb0 TC rules
Add -Wall compiler flag
tcmmd: fix some compiler warnings
version 0.1.11