run.sh: more userfriendly "stale configs" message

Make the message easy to understand at first glance, print what needs to
be done to regenerate the configs. Add an empty line before listing the
stale file that has been found, so it stands out from the (at this
point) less relevant path listings. It looks like the following now:

$ ./run.sh
using config file '/home/user/code/osmo-dev/net/config_2g3g_osmith'
on templates '/home/user/code/osmo-dev/net/tmpl_std'
with NET_DIR '/home/user/code/osmo-dev/net/osmith'

Stale: '/home/user/code/osmo-dev/net/tmpl_std/run.sh' is newer than 'run.sh'

WARNING: STALE CONFIGS - your net configs are older than the templates they should be based on!
 * Hit enter to continue, and use the stale config files
 * Hit ^C and run 'make regen' to regenerate your configs

Change-Id: If225e094619a07a228e0e2f337153ee18cdb420c
2 files changed