Improved llvm-namespace-comment check.

Summary:
Handle various forms of existing namespace closing comments, fix
existing comments with wrong namespace name, ignore short namespaces.

The state of this check now seems to be enough to enable it by default to gather
user feedback ;)

Reviewers: klimek

Reviewed By: klimek

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D3825

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@209141 91177308-0d34-0410-b5e6-96231b3b80d8
Added a comment

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@209146 91177308-0d34-0410-b5e6-96231b3b80d8
Merge pull request #2 from llvm-mirror/master

git pull