Remove OpenSSL engine use from racoon

The Android instructions in the OpenSSL directory indicates to remove
engines, so we should not attempt to initialize engines.
diff --git a/config.h b/config.h
index b0fb71b..306037e 100644
--- a/config.h
+++ b/config.h
@@ -6,7 +6,6 @@
 #undef ENABLE_DPD
 
 #define HAVE_OPENSSL_AES_H
-#define HAVE_OPENSSL_ENGINE_H
 #define WITH_SHA2
 #define HAVE_SHA2_IN_SHA_H