Remove SSL3_FLAGS_POP_BUFFER.

This is an experimental flag that dates back to SSLeay 0.8.1b or earlier. It's
never set internally and never set in consumers.

Change-Id: I922583635c9f3d8d93f08f1707531ad22a26ae6a
Reviewed-on: https://boringssl-review.googlesource.com/2214
Reviewed-by: Adam Langley <agl@google.com>
4 files changed