MXS-1300: Resolved the promise for help commands

The promise returned by the `execute` MaxCtrl library function is now
properly resolved also for `help` type commands.

maxctrl/lib/core.js

@@ -102,7 +102,7 @@ module.exports.execute = function(argv, opts) {
                 if (err) {
                     reject(err.message)
                 } else if (output) {
-                    logger.log(output)
+                    resolve(output)
                 }
             })
     })

maxctrl/maxctrl.js

@@ -15,6 +15,12 @@
 
 var maxctrl = require('./lib/core.js')
 
+function print(out) {
+    if (out) {
+        console.log(out)
+    }
+}
+
 // Mangle the arguments if we are being called from the command line
 if (process.argv[0] == process.execPath) {
     process.argv.shift()
@@ -23,12 +29,4 @@ if (process.argv[0] == process.execPath) {
 }
 
 maxctrl.execute(process.argv)
-    .then(function(out) {
+    .then(print, print)
-        if (out) {
-            console.log(out)
-        }
-    }, function(out) {
-       if (out) {
-            console.log(out)
-        }
-    })

maxctrl/test/special.js

@@ -64,6 +64,12 @@ describe("Library invocation", function() {
             .should.be.rejected
     })
 
+    it('command help', function() {
+        var opts = { extra_args: [ '--quitet'] }
+        return ctrl.execute('help list'.split(' '), opts)
+            .should.be.fulfilled
+    })
+
     it('connection failure', function() {
         stopMaxScale()
             .then(function() {