unifdef a bunch of OPENSSL_NO_* ifdefs.

Get all this stuff out of the way.

- OPENSSL_NO_MD5
- OPENSSL_NO_SHA
- OPENSSL_NO_EC
- OPENSSL_NO_ECDSA
- OPENSSL_NO_ECDH
- OPENSSL_NO_NEXTPROTONEG
- OPENSSL_NO_DH
- OPENSSL_NO_SSL3
- OPENSSL_NO_RC4
- OPENSSL_NO_RSA

Also manually removed a couple instances of OPENSSL_NO_DSA that seemed to be
confused anyway. Did some minor manual cleanup. (Removed a few now-pointless
'if (0)'s.)

Change-Id: Id540ba97ee22ff2309ab20ceb24c7eabe766d4c4
Reviewed-on: https://boringssl-review.googlesource.com/1662
Reviewed-by: Adam Langley <agl@google.com>
29 files changed