Fix wrong exit code on failure to read /proc/meminfo.
Fix wrong exit code on failure to read /proc/meminfo.

Commit

    2f5f8b55 - Use new fatal() helper instead of fprintf+exit

changed the code to use exit code 102 for two cases, when before
one of them used 103 -- likely a copy-paste error.

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