test/system: speed up podman kube play tests

use a command that stops on SIGTERM not sleep, that way the tests can
continue to use podman kube down without waiting for the full stop
timeout every time.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

test/system/700-play.bats

@@ -31,8 +31,7 @@ metadata:
 spec:
   containers:
   - command:
-    - sleep
-    - \"100\"
+    - /home/podman/pause
     env:
     - name: PATH
       value: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin