"
The size_estimates_mutation_reader call for global proxy
to get database from. The database is used to find keyspaces
to work with. However, it's safe to keep the local database
refernece on the reader itself.
tests: unit(debug)
"
* 'br-no-proxy-in-size-estimate-reader' of https://github.com/xemul/scylla:
size_estimate_reader: Use local db reference not global
size_estimate_reader: Keep database reference on mutation reader
size_estimate_reader: Keep database reference on virtual_reader