LP#1329872 - marc_export exit when required IDs are missing

LP#1329872 - marc_export exit when required IDs are missing

The marc_export script would handle being passed invalid or empty
IDs as if you had the --all flag selected.  So if you accidentally
generated a file with a list of BIB id numbers that was empty and
passed it to the script, you would end up with an export of all bibs
in the system instead of an empty export.

Testing Notes:

=== Before fix ===

Create an empty file, or a file that just contains "id".

$ touch input1
$ echo "id" > input2

All these commands should result in a full export of all bibs.

$ cat ./input1 | marc_export
$ cat ./input2 | marc_export
$ echo "id" | marc_export
$ cat ./input1 | marc_export --pipe

=== After fix ===

Try the same commands as above, and the marc_export
script should error out each time.

Signed-off-by: Josh Stompro <stomproj@larl.org>
Signed-off-by: Chris Sharp <csharp@georgialibraries.org>