classify: "classify filter ..." debug CLI cleanup

classify: "classify filter ..." debug CLI cleanup

The pcap trace filter initial table index lives in
cm->filter_set_by_sw_if_index [0], which corresponds to the "local0"
interface. Debug cli makes sure that folks don't accidentally specify
the "local0" interface. At least it does now...

Fix the "vlib format.c code coverage" test in test/test_vlib.py.

Type: fix
Change-Id: I35320bc2c8f0c6f1f8c12e3529d1938548185151
Signed-off-by: Dave Barach <[email protected]>
(cherry picked from commit 29c6132108be68feb11c8d9bfaaf674cba86ee33)