Merge #9794: Minor update to qrencode package builder
Summary:
backport PR9794 https://github.com/bitcoin/bitcoin/pull/9794/files
1bfe6b4 Use package name variable inside $(package)_file_name variable (Mitchell Cash)
Test Plan: build
Reviewers: jasonbcox, Fabien, #bitcoin_abc, deadalnix
Reviewed By: Fabien, #bitcoin_abc
Differential Revision: https://reviews.bitcoinabc.org/D3006