MB-9423: Add a 30 second timeout to cbepctl and cbstats

Change-Id: I392a9efab924de99e9ddbf4171b368b02327453d
Reviewed-on: http://review.couchbase.org/31273
Reviewed-by: abhinav dangeti <abhinav@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>
Insert assert to catch xdcr bug

Change-Id: I411709086db5a31885c6c6787e1b20384c864232