don't perform for-effect work inside assert
don't perform for-effect work inside assert

Because assert can be compiled-away if NDEBUG is defined.

Change-Id: Ic38d9e2bca79667343d94d44e94350158d20bb47
Reviewed-on: http://review.couchbase.org/29394
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Filipe David Borba Manana <e0fcd583df77ec6c08e6d1257619cc1216ddc994@gmail.com>
Tested-by: Filipe David Borba Manana <e0fcd583df77ec6c08e6d1257619cc1216ddc994@gmail.com>

t3rm1n4l/couchstore,abhinavdangeti/couchstore,couchbaselabs/couchstore,jimwwalker/couchstore,abhinavdangeti/couchstore,t3rm1n4l/couchstore,vmx/couchstore,jimwwalker/couchstore,t3rm1n4l/couchstore,jimwwalker/couchstore,vmx/couchstore,couchbaselabs/couchstore,abhinavdangeti/couchstore,vmx/couchstore,couchbaselabs/couchstore