VOL-4151: Code improvement to use static const instead of static
to allow for compiler optimization.
Also fixed SECURITY.md document as the sample commands were not
ready for copy/paste earlier.

Change-Id: I7fdfa03ed3e6677466fb78b8ea8532d4f5c0a6da
diff --git a/agent/src/core_utils.cc b/agent/src/core_utils.cc
index a80b8d6..2aad9fd 100644
--- a/agent/src/core_utils.cc
+++ b/agent/src/core_utils.cc
@@ -1844,7 +1844,7 @@
 }
 
 std::pair<grpc_ssl_client_certificate_request_type, bool> get_grpc_tls_option(const char* tls_option) {
-    static std::map<std::string,grpc_ssl_client_certificate_request_type> grpc_security_option_map = {{"GRPC_SSL_DONT_REQUEST_CLIENT_CERTIFICATE",
+    static const std::map<std::string,grpc_ssl_client_certificate_request_type> grpc_security_option_map = {{"GRPC_SSL_DONT_REQUEST_CLIENT_CERTIFICATE",
                                                                                                         grpc_ssl_client_certificate_request_type::GRPC_SSL_DONT_REQUEST_CLIENT_CERTIFICATE},
                                                                                                       {"GRPC_SSL_REQUEST_CLIENT_CERTIFICATE_BUT_DONT_VERIFY",
                                                                                                         grpc_ssl_client_certificate_request_type::GRPC_SSL_REQUEST_CLIENT_CERTIFICATE_BUT_DONT_VERIFY},