clang-format: When a line is formatted, also format subsequence lines if their indent is off.

Summary: This is especially important so that if a change is solely inserting a block around a few statements, clang-format-diff.py will still clean up and add indentation to the inner parts.

Reviewers: klimek

Subscribers: cfe-commits, klimek

Differential Revision: http://reviews.llvm.org/D14105

llvm-svn: 251474