The shell command used to list all files but the libc's ones
introduced in commit 95d5353c was incorrect. It was listing
subdirectories without referencing their parent directories.
This patch fixes it.

Also, the command used to invoke the checkpatch.pl script is now
printed when V=1.

Change-Id: Ie2f1e74f60d77e38c25e717cffa44ca03baec7b2