ipsec_manager: Enable SonicWall compatibility

Use the new upstream flag to accept frames from SonicWall.

BUG=chromium:334620
TEST=Authenticate to SonicWall

Change-Id: I19d277f66cd105e1e5aaaaaef35db24aabfaa6a5
Reviewed-on: https://chromium-review.googlesource.com/195408
Reviewed-by: Ben Chan <benchan@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
Commit-Queue: Paul Stewart <pstew@chromium.org>
diff --git a/ipsec_manager.cc b/ipsec_manager.cc
index b9020fc..5a35c6b 100644
--- a/ipsec_manager.cc
+++ b/ipsec_manager.cc
@@ -352,6 +352,7 @@
   config.append("  }\n");
   config.append("}\n");
   config.append("charon {\n");
+  config.append("  accept_unencrypted_mainmode_messages = yes\n");
   config.append("  ignore_routing_tables = 0\n");
   config.append("  install_routes = no\n");
   config.append("  routing_table = 0\n");
diff --git a/ipsec_manager_test.cc b/ipsec_manager_test.cc
index dfa600f..7be8530 100644
--- a/ipsec_manager_test.cc
+++ b/ipsec_manager_test.cc
@@ -275,6 +275,7 @@
       "  }\n"
       "}\n"
       "charon {\n"
+      "  accept_unencrypted_mainmode_messages = yes\n"
       "  ignore_routing_tables = 0\n"
       "  install_routes = no\n"
       "  routing_table = 0\n"