Stop using the word 'buffer' everywhere.

buffer buffer buffer buffer buffer. At some point, words lose their meaning if
they're used too many times. Notably, the DTLS code can't decide whether a
"buffered message" is an incoming message to be reassembled or an outgoing
message to be (re)transmitted.

Change-Id: Ibdde5c00abb062c603d21be97aff49e1c422c755
Reviewed-on: https://boringssl-review.googlesource.com/8500
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/internal.h b/ssl/internal.h
index 710fdd3..4ecf6e0 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -1058,7 +1058,7 @@
 
 int dtls1_send_change_cipher_spec(SSL *ssl, int a, int b);
 int dtls1_send_finished(SSL *ssl, int a, int b, const char *sender, int slen);
-int dtls1_retransmit_buffered_messages(SSL *ssl);
+int dtls1_retransmit_outgoing_messages(SSL *ssl);
 void dtls1_clear_record_buffer(SSL *ssl);
 int dtls1_parse_fragment(CBS *cbs, struct hm_header_st *out_hdr,
                          CBS *out_body);