Require ECDHE for False Start.

This adds just enough of an implementation of ECDHE_RSA to tlslite to
support it on the server side.

It also rolls BoringSSL e2e1326..4d78718 to pick up the corresponding
BoringSSL change. Summary of changes available at:

https://boringssl.googlesource.com/boringssl/+log/e2e1326..4d78718

BUG=460271

Review URL: https://codereview.chromium.org/1057733002

Cr-Original-Commit-Position: refs/heads/master@{#323645}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 8f7efab800fc6987499c5365fce22349e3a4ef50
diff --git a/testserver.py b/testserver.py
index 19409d2..bda4f90 100755
--- a/testserver.py
+++ b/testserver.py
@@ -2258,11 +2258,11 @@
     self.option_parser.add_option('--ssl-key-exchange', action='append',
                                   help='Specify the key exchange algorithm(s)'
                                   'that will be accepted by the SSL server. '
-                                  'Valid values are "rsa", "dhe_rsa". If '
-                                  'omitted, all algorithms will be used. This '
-                                  'option may appear multiple times, '
-                                  'indicating multiple algorithms should be '
-                                  'enabled.');
+                                  'Valid values are "rsa", "dhe_rsa", '
+                                  '"ecdhe_rsa". If omitted, all algorithms '
+                                  'will be used. This option may appear '
+                                  'multiple times, indicating multiple '
+                                  'algorithms should be enabled.');
     # TODO(davidben): Add ALPN support to tlslite.
     self.option_parser.add_option('--enable-npn', dest='enable_npn',
                                   default=False, const=True,