Pull in r199571 from upstream clang trunk (by Ted Kremenek):

Pull in r199571 from upstream clang trunk (by Ted Kremenek):

  Harden InitListExpr::isStringLiteralInit() against getInit()
  returning null.

  This led to a crash on invalid code (sorry, no good test case).

  Fixes <rdar://problem/15831804>.

This fixes an assertion when compiling certain incorrect code, as
reported upstream in http://llvm.org/PR22684 .

Direct commit to stable/10 and stable/9, since head has clang 3.5.1,
which already includes this change.

Reported by:	hbowden@securelabsllc.com

git-svn-id: svn://svn.freebsd.org/base/stable/10@279289 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f