Rename algorithm2 to algorithm_prf.

It's purely the PRF function now, although it's still different from the
rest due to the _DEFAULT field being weird.

Change-Id: Iaea7a99cccdc8be4cd60f6c1503df5be2a63c4c5
Reviewed-on: https://boringssl-review.googlesource.com/5614
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/internal.h b/ssl/internal.h
index 5873570..7f2dd52 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -202,8 +202,7 @@
 #define SSL_TLSV1 SSL_SSLV3
 #define SSL_TLSV1_2 0x00000004L
 
-/* Bits for |algorithm2| (handshake digests and other extra flags). */
-
+/* Bits for |algorithm_prf| (handshake digest). */
 #define SSL_HANDSHAKE_MAC_MD5 0x10
 #define SSL_HANDSHAKE_MAC_SHA 0x20
 #define SSL_HANDSHAKE_MAC_SHA256 0x40
@@ -1181,7 +1180,7 @@
  * the wire version except at API boundaries. */
 uint16_t ssl3_version_from_wire(SSL *s, uint16_t wire_version);
 
-uint32_t ssl_get_algorithm2(SSL *s);
+uint32_t ssl_get_algorithm_prf(SSL *s);
 int tls1_process_sigalgs(SSL *s, const CBS *sigalgs);
 
 /* tls1_choose_signing_digest returns a digest for use with |ssl|'s private key