allow setting of ciphers in credentials

fixes #873

lib/crypto.js

@@ -68,6 +68,8 @@ exports.createCredentials = function(options) {
 
   if (options.cert) c.context.setCert(options.cert);
 
+  if (options.ciphers) c.context.setCiphers(options.ciphers);
+
   if (options.ca) {
     if (Array.isArray(options.ca)) {
       for (var i = 0, len = options.ca.length; i < len; i++) {

lib/tls.js

@@ -723,6 +723,7 @@ function Server(/* [options], listener */) {
       key: self.key,
       cert: self.cert,
       ca: self.ca,
+      ciphers: self.ciphers,
       secureProtocol: self.secureProtocol,
       secureOptions: self.secureOptions,
       crl: self.crl
@@ -796,6 +797,7 @@ Server.prototype.setOptions = function(options) {
   if (options.ca) this.ca = options.ca;
   if (options.secureProtocol) this.secureProtocol = options.secureProtocol;
   if (options.crl) this.crl = options.crl;
+  if (options.ciphers) this.ciphers = options.ciphers;
   if (options.secureProtocol) this.secureProtocol = options.secureProtocol;
   if (options.secureOptions) this.secureOptions = options.secureOptions;
 };