Disable exceptions for cobalt_core_unittests

We will soon start passing -fno-exceptions as ldflag in the Fuchsia
build to ensure that the right libc++ is being linked. This breaks
cobalt_core_tests target which links curl_handle target that uses
exceptions, so we need to disable exceptions for this target as well
to make sure that -fno-exceptions isn't passed to this target.

Change-Id: Ic1f2f9fd9fc264d12b199eb38d8ddb14ec6ec3b8
diff --git a/BUILD.gn b/BUILD.gn
index 77a7014..1fd4b51 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -46,6 +46,8 @@
     "//third_party/boringssl:crypto",
     "//third_party/googletest:gtest_main",
   ]
+
+  configs -= [ "//build/config:no_exceptions" ]
 }
 
 if (is_fuchsia_tree) {
diff --git a/keys/BUILD.gn b/keys/BUILD.gn
index 55eafd0..dd0aef9 100644
--- a/keys/BUILD.gn
+++ b/keys/BUILD.gn
@@ -32,6 +32,10 @@
     "//third_party/tink/proto:tink_proto",
   ]
   public_configs = [ "//third_party/tink:tink_config" ]
+  configs -= [
+    "//build/config:no_exceptions",
+    "//build/config:no_rtti",
+  ]
 }
 
 group("tests") {