This commit attempts to address the following:
 * Make sure swss container is indeed up and running before running any commands
   on it. In case where swss container is not fully up when swss.sh attempts to
   create swss:/ready file using "docker exec swss$DEV touch", the command can
   fail silently and can cause swssconfig to wait forever leading to missing IP
   decap configuration among other things. Add a wait so that docker commands
   are run only after swss container status is "Running"
*  Add a log when swss:/ready file is created or if the file creation fails so
   that it becomes easier to debug such scenarios in the future

Signed-off-by: Prabhat Aravind <paravind@microsoft.com>

…ms as well

Signed-off-by: Prabhat Aravind <paravind@microsoft.com>