Update to make dtrace-provider optional.

lib/dtrace.js

@@ -79,7 +79,28 @@ var SERVER_PROBES = {
 
 module.exports = function () {
   if (!SERVER_PROVIDER) {
-    SERVER_PROVIDER = dtrace.createDTraceProvider('ldapjs');
+    try {
+      var dtrace = require('dtrace-provider');
+      SERVER_PROVIDER = dtrace.createDTraceProvider('restify');
+    } catch (e) {
+      SERVER_PROVIDER = {
+          fire: function () {
+          },
+          enable: function () {
+          },
+          addProbe: function () {
+              var p = {
+                  fire: function () {
+                  }
+              };
+              return (p);
+          },
+          removeProbe: function () {
+          },
+          disable: function () {
+          }
+      };
+    }
 
     Object.keys(SERVER_PROBES).forEach(function (p) {
       var args = SERVER_PROBES[p].splice(0);

package.json

@@ -30,10 +30,12 @@
     "asn1": "0.1.11",
     "assert-plus": "0.1.2",
     "bunyan": "0.21.1",
-    "dtrace-provider": "0.2.8",
     "nopt": "2.1.1",
     "pooling": "0.4.5"
   },
+  "optionalDependencies": {
+    "dtrace-provider": "0.2.8"
+  },
   "devDependencies": {
     "tap": "0.4.1",
     "node-uuid": "1.4.0"