Switch ssl_privkey to C++.

In the process, merge the old canary function back in.

Bug: 132
Change-Id: Ib455320ecea67c839d0b4ac3882669d24f832b74
Reviewed-on: https://boringssl-review.googlesource.com/17765
Reviewed-by: Steven Valdez <svaldez@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
diff --git a/ssl/CMakeLists.txt b/ssl/CMakeLists.txt
index d825827..d2fe849 100644
--- a/ssl/CMakeLists.txt
+++ b/ssl/CMakeLists.txt
@@ -24,8 +24,7 @@
   ssl_ecdh.cc
   ssl_file.cc
   ssl_lib.cc
-  ssl_privkey.c
-  ssl_privkey_cc.cc
+  ssl_privkey.cc
   ssl_session.c
   ssl_stat.c
   ssl_transcript.c