bump sinon-rails

Gemfile

@@ -288,7 +288,7 @@ group :development, :test do
   gem "jasmine",                   "2.2.0"
   gem "jasmine-jquery-rails",      "2.0.3"
   gem "rails-assets-jasmine-ajax", "3.1.1", source: "https://rails-assets.org"
-  gem "sinon-rails",               "1.10.3"
+  gem "sinon-rails",               "1.15.0"
 
   # silence assets
   gem "quiet_assets", "1.1.0"

Gemfile.lock

@@ -673,7 +673,7 @@ GEM
       rack (~> 1.4)
       rack-protection (~> 1.4)
       tilt (>= 1.3, < 3)
-    sinon-rails (1.10.3)
+    sinon-rails (1.15.0)
       railties (>= 3.1)
     slop (3.6.0)
     spring (1.3.6)
@@ -858,7 +858,7 @@ DEPENDENCIES
   simple_captcha2 (= 0.3.4)
   simplecov (= 0.10.0)
   sinatra (= 1.4.6)
-  sinon-rails (= 1.10.3)
+  sinon-rails (= 1.15.0)
   spring (= 1.3.6)
   spring-commands-cucumber (= 1.0.1)
   spring-commands-rspec (= 1.0.4)