Convert the SRTP extension to the new system

Change-Id: I12f1d06562c34d357d82bbde7e5d0c15096046e6
Reviewed-on: https://boringssl-review.googlesource.com/5463
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/tls1.h b/include/openssl/tls1.h
index b3be3e1..b68db3d 100644
--- a/include/openssl/tls1.h
+++ b/include/openssl/tls1.h
@@ -209,7 +209,7 @@
 #define TLSEXT_TYPE_signature_algorithms 13
 
 /* ExtensionType value from RFC5764 */
-#define TLSEXT_TYPE_use_srtp 14
+#define TLSEXT_TYPE_srtp 14
 
 /* ExtensionType value from RFC5620 */
 #define TLSEXT_TYPE_heartbeat 15