Add |X509_METHOD| and, using it, move many functions to ssl_x509.c.

Change-Id: I266af0c2bdcebcc1dd1026f816b9ef6ece5a592f
Reviewed-on: https://boringssl-review.googlesource.com/13581
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

ssl/tls_method.c

diff --git a/ssl/tls_method.c b/ssl/tls_method.c
index 70683e4..5533dfd 100644
--- a/ssl/tls_method.c
+++ b/ssl/tls_method.c
@@ -161,6 +161,7 @@
   static const SSL_METHOD kMethod = {
       0,
       &kTLSProtocolMethod,
+      &ssl_crypto_x509_method,
   };
   return &kMethod;
 }
@@ -175,6 +176,7 @@
   static const SSL_METHOD kMethod = {
       TLS1_2_VERSION,
       &kTLSProtocolMethod,
+      &ssl_crypto_x509_method,
   };
   return &kMethod;
 }
@@ -183,6 +185,7 @@
   static const SSL_METHOD kMethod = {
       TLS1_1_VERSION,
       &kTLSProtocolMethod,
+      &ssl_crypto_x509_method,
   };
   return &kMethod;
 }
@@ -191,6 +194,7 @@
   static const SSL_METHOD kMethod = {
       TLS1_VERSION,
       &kTLSProtocolMethod,
+      &ssl_crypto_x509_method,
   };
   return &kMethod;
 }
@@ -199,6 +203,7 @@
   static const SSL_METHOD kMethod = {
       SSL3_VERSION,
       &kTLSProtocolMethod,
+      &ssl_crypto_x509_method,
   };
   return &kMethod;
 }