Fixes following error reported by clang-9 analyzer:
examples/server.c:244:2: warning: Value stored to 'argc' is never read
argc -= optind;
^ ~~~~~~
examples/server.c:245:2: warning: Value stored to 'argv' is never read
argv += optind;
^ ~~~~~~
Signed-off-by: Petr Štetiar <ynezz@true.cz>