Use -Wno-error for newly added warnings

This is so the warnings are written to the logs.  They just don't turn into an error.
Test: python toolchain/llvm/android/test_compiler.py
--no-redirect-stderr --build-only -t aosp_angler-eng ./
Bug: http://b/62872741

Change-Id: I75ec9d48584f0ab4711b629ff773996233323563
1 file changed