test/shm_size.bats: fix SC2002
test/shm_size.bats: fix SC2002

Fix shellcheck's SC2002 "useless cat" warning.

Also fix excessive run usage (we only need to check for non-zero
status, so `! cmd` is enough).

Signed-off-by: Kir Kolyshkin <3a017b8ddb3f9cf3e4a59978b004111bdeb97f08@gmail.com>

kubernetes-incubator/cri-o,kubernetes-incubator/cri-o,kubernetes-incubator/cri-o,kubernetes-incubator/ocid,kubernetes-incubator/ocid,kubernetes-incubator/ocid,nalind/cri-o,kubernetes-incubator/cri-o,nalind/cri-o,nalind/cri-o