[PATCH] Sema: Do not allow template declarations inside local classes

[Yunzhong Gao]

  This is essentially the same implementation as what I proposed a few weeks ago,
  http://llvm-reviews.chandlerc.com/D575.
  On that review, I was waiting to hear from Faisal who has started adding support
  for local member templates to clang, and I am not sure if he needs this support
  for any language extensions.

  I feel that it is wrong to just remove tests without also removing relevant compiler
  changes, because that leaves a feature in the compiler without any tests. e.g.,
  If one wants to remove the following two tests, he/she should either revert r184903
  or write some different tests.
  test/PCH/cxx-local-templates.cpp
  test/PCH/cxx1y-local-templates.cpp

http://llvm-reviews.chandlerc.com/D1866