Don't close stdin on maxmind_db spawn error
This solves the following issue:
In cases where mmdbresolve
fails to execute (e.g. when it's simply
missing from a tree) the spawn fails such that a zero initialized file
descriptor is closed (i.e. stdin). The close is silent, unless one
executes something like tshark -r - ...
where a bad file descriptor
is reported then.
Edited by Georg Sauthoff