[clang-tidy] Do not show incorrect fix in modernize-make-unique

Summary:
The case when initialize_list hides behind an implicit case was not
handled before.

Reviewers: aaron.ballman

Reviewed By: aaron.ballman

Subscribers: xazax.hun, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D61642

llvm-svn: 360231