Only call SSL_CTX_free if DO_SSL is defined.

Thanks to Paul Belanger for pointing out this error.
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Merged revisions 367416 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 367417 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@367418 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/tcptls.c

@@ -417,10 +417,12 @@ int ast_ssl_setup(struct ast_tls_config *cfg)
 
 void ast_ssl_teardown(struct ast_tls_config *cfg)
 {
+#ifdef DO_SSL
 	if (cfg->ssl_ctx) {
 		SSL_CTX_free(cfg->ssl_ctx);
 		cfg->ssl_ctx = NULL;
 	}
+#endif
 }
 
 struct ast_tcptls_session_instance *ast_tcptls_client_start(struct ast_tcptls_session_instance *tcptls_session)