libweave: Fix switch case fallthrough

Fix fall-through warning reported with
-Wimplicit-fallthrough build flag.
Rearrange header files to fix cros lint warning.

The following fall-through warning was fixed:
security_manager.cc:245:5: error: unannotated fall-through between
switch labels [-Werror,-Wimplicit-fallthrough]

BUG=chromium:904913
TEST=package build passes with flag -Wimplicit-fallthrough

Cq-Depend: chromium:1643102
Change-Id: I5e2da4487855a598edf01286014fed1badecdd1c
Reviewed-on: https://chromium-review.googlesource.com/c/weave/libweave/+/1646879
Tested-by: Denis Nikitin <denik@chromium.org>
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
Commit-Queue: Denis Nikitin <denik@chromium.org>
1 file changed