Fix executable permissions

Caught by lint, this permission change was accidentally introduced
by commit 42cb3819f1a1f536105faac81ffc150f3da90a80. Restore the
correct permissions and while I'm at it add a missing whack-bang
to config/ltmain.sh.

lint: executable-not-elf-or-script: zpool_main.c zfs_main.c

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #620