do not segfault on empty filename to escape.
do not segfault on empty filename to escape.

Avoid case where e_exec (and possible others) gives
e_util_filename_escape() a NULL parameter, actually another bug, but
does not hurt to safe guard this one.

By: manio



git-svn-id: 6ac5796aeae0cef97fb47bcc287d4ce899c6fa6e@40979 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33

jordemort/e17,jordemort/e17,jordemort/e17