Revert "FROMGIT: kheaders: prevent `find` from seeing perl temp files"

This reverts commit 32b0477e.

This is necessary to also revert commit 28fa7afc ("FROMLIST:
kheaders: dereferences the source tree"), which is no longer applicable
and it causes conflicts with upstream merge. Note the upstream version
of this FROMGIT will land via merge instead, so no worries.

Cc: Yifan Hong <elsk@google.com>
Change-Id: Ia971787d89b4074298767ec66632e650f56aea45
Signed-off-by: Carlos Llamas <cmllamas@google.com>