Remove unhelpful warning about changing state numbers.

This dates all the way to SSLeay 0.9.0b. At this point the
application/handshake interleave logic in ssl3_read_bytes was already
present:

((
  (s->state & SSL_ST_CONNECT) &&
  (s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
  (s->state <= SSL3_ST_CR_SRVR_HELLO_A)
 ) || (
  (s->state & SSL_ST_ACCEPT) &&
  (s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
  (s->state >= SSL3_ST_SR_CLNT_HELLO_A)
 )

The comment is attached to SSL3_ST_SR_CLNT_HELLO_A, so I suspect this is
what it was about. This logic is gone now, so let's remove that scary
warning.

Change-Id: I45f13b53b79e35d80e6074b0942600434deb0684
Reviewed-on: https://boringssl-review.googlesource.com/6299
Reviewed-by: Adam Langley <alangley@gmail.com>

include/openssl/ssl3.h

@@ -613,7 +613,6 @@ typedef struct ssl3_state_st {
 /* read from client */
 #define SSL3_ST_SR_INITIAL_BYTES (0x240 | SSL_ST_ACCEPT)
 #define SSL3_ST_SR_V2_CLIENT_HELLO (0x241 | SSL_ST_ACCEPT)
-/* Do not change the number values, they do matter */
 #define SSL3_ST_SR_CLNT_HELLO_A (0x110 | SSL_ST_ACCEPT)
 #define SSL3_ST_SR_CLNT_HELLO_B (0x111 | SSL_ST_ACCEPT)
 #define SSL3_ST_SR_CLNT_HELLO_C (0x112 | SSL_ST_ACCEPT)