Fix "Could not set oom_score_adj: Success" message
Fix "Could not set oom_score_adj: Success" message

Error checking was messed up, as fclose overwrites whatever
fprintf may have done.

Fixes https://github.com/rfjakob/earlyoom/issues/90

rfjakob/earlyoom,rfjakob/earlyoom,rfjakob/earlyoom,rfjakob/earlyoom