fix dependency lcg.h in CMakeLists and Makefile.test.include
Summary:
was causing failed gitian
(my bad, was introduced in D2480)
Test Plan: Jason ran the gitian build on this patch successfully.
Reviewers: #bitcoin_abc, deadalnix, jasonbcox
Reviewed By: #bitcoin_abc, jasonbcox
Subscribers: teamcity, schancel
Differential Revision: https://reviews.bitcoinabc.org/D2489