ipcs: fix ipc_sem_get_info fallback case

"ipcs -s -i n" (case id >= 0) was broken since v2.22-254-g1e2418a if /sys
is not usable.

See also comments for commit "ipcs: fix ipc_msg_get_info fallback case".

Signed-off-by: Ruediger Meier <ruediger.meier@ga-group.nl>
ipcs: fix memleak in ipc_*_get_info functions

In case of error (maxid < 0) we do not enter following for loop. It will
return 0 and free the structs afterwards because i is still 0.

Signed-off-by: Ruediger Meier <ruediger.meier@ga-group.nl>
travis-ci: abort if make check fails

make check should work now on current travis build image.

Signed-off-by: Ruediger Meier <ruediger.meier@ga-group.nl>