Do not delete entry if get script returns an error

[coudot]

When using executable plugin as source for the clean phase, entries in destination are deleted even if the script returns an error. The entry should be deleted in destination only if script succeed but returns no entry.

Dec 25 20:57:55 - ERROR - Non zero exit code for runtime: /usr/local/bin/xxx-get.pl, exit code=1
Dec 25 20:57:55 - ERROR - Can't connect to api.xxx:443
Dec 25 20:57:55 - ERROR - Entries count: 0
Dec 25 20:57:55 - INFO  - # Removing object uid=xxx,ou=users,xxx for user-full