scripts/internals: strip all executables

Using a list of files to strip misses a few of them.
Now, scan appropriate directories, and strip all ELF
executables and shared objects.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

reporter_name="Thomas Petazzoni"

reporter_url="http://www.free-electrons.com/"

reporter_comment="Very basic testing only"