Avoid white spaces in file names. NFC

Summary: White spaces in file names are causing Phabricator/SVN to crash.

Reviewers: bkramer

Subscribers: bogner, cfe-commits

Differential Revision: https://reviews.llvm.org/D35203

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@307551 91177308-0d34-0410-b5e6-96231b3b80d8