make sure --show-config doesn't crash main server :-)

lib/server/main.js

@@ -172,8 +172,9 @@ var main = function(args, readyCb, doneCb) {
         return cb(e);
       }
       var versionMismatches = {};
+      var excludedKeys = ["git-sha", "node_bin", "built"];
       _.each(rawConfig, function(deviceConfig, key) {
-        if (deviceConfig.version !== appiumVer && key !== "git-sha" && key !== "node_bin") {
+        if (deviceConfig.version !== appiumVer && !_.contains(excludedKeys, key)) {
           versionMismatches[key] = deviceConfig.version;
         } else if (key === "git-sha") {
           appiumRev = rawConfig['git-sha'];

lib/server/parser.js

@@ -335,7 +335,7 @@ var args = [
   }],
 
   [['--show-config'], {
-    defaultValue: true
+    defaultValue: false
     , dest: 'showConfig'
     , action: 'storeTrue'
     , required: false