Debug Info: fix the line location for cleanup code of a block function

The line information was changed when emitting debug information for all the
DeclRefExprs and we should change it back to get ready for PopClenupBlocks
called from FinishFunction.

rdar://11562117


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171493 91177308-0d34-0410-b5e6-96231b3b80d8