Consumed analysis: assume that non-const reference parameters are initially
in the "uknown" state.  Patch by chris.wailes@gmail.com.  Reviewed by delesley.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@192995 91177308-0d34-0410-b5e6-96231b3b80d8