scripts/clean-includes: Fully skip / ignore files

scripts/clean-includes: Fully skip / ignore files

When clean-includes claims to skip or ignore a file, only the part
that sanitizes use of qemu/osdep.h skips the file.  The part that
looks for duplicate #include does not, and neither does committing to
Git.

The latter can get unrelated stuff included in the commit, but only if
you run clean-includes in a dirty tree, which is unwise.  Messed up
when we added skipping in commit fd3e39a40c "scripts/clean-includes:
Enhance to handle header files".

The former can cause bogus reports for --check-dup-head.  Added in
commit d66253e46a "scripts/clean-includes: added duplicate #include
check", duplicating the prior mistake.

Fix the script to fully skip files.

Fixes: fd3e39a40ca2 ("scripts/clean-includes: Enhance to handle header files")
Fixes: d66253e46ae2 ("scripts/clean-includes: added duplicate #include check")
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20230202133830.2152150-2-armbru@redhat.com>