Omit anonymous and inline namespaces in OneUse symbol names (fixes issue #133).

Instead of using NamedDecl full qualified name, suppress unwritten scopes.  It
makes libc++ symbol names the same as libstdc++.

git-svn-id: http://include-what-you-use.googlecode.com/svn/trunk@550 812d1f90-f944-d88a-411a-122bdc93e1ea