Update rpc_spec, .gitmodules, some JSs in accordance with code review at #357.

Author: shiniwat

.gitmodules

@@ -1,4 +1,3 @@
 [submodule "lib/rpc_spec"]
 	path = lib/rpc_spec
-	url = https://github.com/shiniwat/rpc_spec.git
-	branch = feature/issue-222
+	url = https://github.com/smartdevicelink/rpc_spec.git

lib/js/src/streaming/video/_VideoStreamingParameters.js

@@ -105,7 +105,7 @@ class _VideoStreamingParameters {
             this._format = formats[0];
         }
         const fps = capability.getPreferredFPS();
-        if (fps != null) {
+        if (fps !== null) {
             this._frameRate = fps;
         }
     }

lib/rpc_spec

@@ -94,6 +94,7 @@ describe('VideoStreamingParametersTest', function () {
         capability.setPreferredFPS(15);
         params.update(capability);
         Validator.assertEquals(params.getFormat(), format);
+        Validator.assertEquals(params.getFrameRate(), 15);
 
         done();
     });