Fix SSL and SSL_CTX ex_data variable names.

Forgot to fix these when I fixed the headers.

Change-Id: Ie45e624abc993e16e2d5a872ef00dba9029a38df
Reviewed-on: https://boringssl-review.googlesource.com/5891
Reviewed-by: Adam Langley <agl@google.com>
1 file changed