MB-7492: print 64-bit value as long long

Previous code used %X which is unsigned. On i386 that's 2 words pushed
on stack for 64-bit options, but only one word is consumed by
sprintf. Causing next argument which is pointer to string to consume
garbage and crash trying to print it.

Change-Id: I43f499e26487de4b5c52cd0cf06b43bad70d8229
Reviewed-on: http://review.couchbase.org/23725
Reviewed-by: Jin Lim <jin@couchbase.com>
Tested-by: Jin Lim <jin@couchbase.com>