scripts: When zotonic is not running, echo the output of erl_call

This is to ease debugging situations where Zotonic in fact *is*
running but erl_call thinks it isn't.
(cherry picked from commit ea467258206a44fe946f76107573e515d2002966)
scripts: Fix typo in zotonic-update
(cherry picked from commit 2b9dbac3522e80aeba94dae05858e9217bdbd6d8)