server: send current version of cypress when checking for updates, fixes #456

packages/server/lib/updater.coffee

@@ -40,6 +40,7 @@ NwUpdater.prototype.checkNewVersion = (cb) ->
     request.get({
       url: @manifest.manifestUrl,
       headers: {
+        "x-cypress-version": pkg.version
         "x-machine-id": id
       }
     }, gotManifest.bind(@))

packages/server/test/unit/updater_spec.coffee

@@ -47,6 +47,15 @@ describe "lib/updater", ->
 
       @updater = Updater({})
 
+    it "sends x-cypress-version", (done) ->
+      @updater.getClient().checkNewVersion =>
+        expect(@get).to.be.calledWithMatch({
+          headers: {
+            "x-cypress-version": pkg.version
+          }
+        })
+        done()
+
     it "sends x-machine-id", (done) ->
       nmi.machineId()
       .then (id) =>
@@ -57,7 +66,6 @@ describe "lib/updater", ->
             }
           })
           done()
-      return
 
     it "sends x-machine-id as null on error", (done) ->
       @sandbox.stub(nmi, "machineId").rejects(new Error())
@@ -70,7 +78,6 @@ describe "lib/updater", ->
         })
 
         done()
-      return
 
   context "#check", ->
     beforeEach ->