BUG/MINOR: tools: make str2sa_range() report unresolvable addresses

If an environment variable is used in an address, and is not set, it's
silently considered as ":" or "0.0.0.0:0" which is not correct as it
can hide environment issues and lead to unexpected behaviours. Let's
report this case when it happens.

This fix should be backported to 1.5.
(cherry picked from commit 9f69f46d1f1b1d116c00b4b0483c519747f977b7)
1 file changed