MXS-1220: Add more validation checks to request JSON

The requests that send a body should define at least a `data` member.

Added a simple test that checks that bad requests are rejected. This test
should be expanded to check that the returned error body contains the
correct members.

server/core/test/rest-api/test/errors.js

@@ -0,0 +1,21 @@
+require("../utils.js")()
+
+
+describe("Errors", function()
+{
+    before(startMaxScale)
+
+    it("error on invalid PUT request", function()
+    {
+        return request.put(base_url + "/servers/server1", { json: {this_is: "a test"}})
+               .should.be.rejected
+    })
+
+    it("error on invalid POST request", function()
+    {
+        return request.post(base_url + "/servers", { json: {this_is: "a test"}})
+               .should.be.rejected
+    })
+
+    after(stopMaxScale)
+});