Fix bug in suggested fix that truncated variable names to 1 character.

Summary:
Fix bug in suggested fix that truncated variable names to 1 character.
Also, rework the suggested fix to try to remove unnecessary whitespace.

Reviewers: alexfh, aaron.ballman

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D13899

llvm-svn: 252773