Fix a few Clang assertions thrown by llvm-rs-cc

Bug: 19545955

- Mark global or local RS objects as 'Used' when inserting calls to
  rsrClearObject.
- Mark an integer variable created by ClearRSArrayObject for iteration
  as 'used'.
- Pass a valid DeclarationNameInfo while creating a MemberExpr.

Change-Id: I591b98a7840f0d9117a751daef97df16aeba8206
1 file changed