Move EVP_R_COMMAND_NOT_SUPPORTED into individual EVP_PKEY ctrl hooks.

This removes another place where we're internally sensitive to the
success/failure conditions.

Change-Id: I18fecf6457e841ba0afb718397b9b5fd3bbdfe4c
Reviewed-on: https://boringssl-review.googlesource.com/3872
Reviewed-by: Adam Langley <agl@google.com>
6 files changed