ipcs: make sure to parse whole lines for shm_data

ipcs: make sure to parse whole lines for shm_data

We want to parse 16 columns _per_row_ without mixing them up. The
existing code is unsafe for more or less columns and could even
run into endless loops. This patch assures that we parse row-wise
and really skip lines with columns != 16.

Probably somehow we could have also done this with fscanf() only.
Using fgets() additionally makes the code more easy to read and
to improve later.

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