Fix a couple of minor compiler warnings.

One about a possible uninitialised variable (incorrect, but it's easier
to keep the compiler happy) and one warning about "const static" being
backwards.

Change-Id: Ic5976a5f0b48f32e09682e31b65d8ea1c27e5b88
Reviewed-on: https://boringssl-review.googlesource.com/2632
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>