Rename DeclContext::getLookupContext to getRedeclContext and change its semantics slightly. No functionality change in the absence of inline namespaces. Also, change a few places where inline namespaces actually make a difference to be prepared for them.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@112563 91177308-0d34-0410-b5e6-96231b3b80d8
16 files changed