tools build: Add test for missing include

The current build framework fails to cope with header file removal. The
reason is that the removed header file stays in the .cmd file target
rule and forces the build to fail.

This issue is fixed and explained in the following patches.

Adding a new build test that simulates header removal.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1443004442-32660-3-git-send-email-jolsa@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>