Remove remnants of export cipher suite selection.

Splitting the strength mask between SSL_EXP_MASK and SSL_STRONG_MASK no longer
does anything. Also remove the SSL_NOT_EXP bit and condense the strength bits.

Change-Id: I9e61acdde008c3ce06bb37f78a72099fc53ed080
Reviewed-on: https://boringssl-review.googlesource.com/1757
Reviewed-by: Adam Langley <agl@google.com>
3 files changed