Drop rspec-instafail dependency

Gemfile

@@ -256,7 +256,6 @@ group :test do
 
   gem "fixture_builder",   "0.4.1"
   gem "fuubar",            "2.0.0"
-  gem "rspec-instafail",   "0.5.0", require: false
   gem "test_after_commit", "1.0.0"
 
   # Cucumber (integration tests)

Gemfile.lock

@@ -662,8 +662,6 @@ GEM
     rspec-expectations (3.4.0)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.4.0)
-    rspec-instafail (0.5.0)
-      rspec
     rspec-mocks (3.4.1)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.4.0)
@@ -899,7 +897,6 @@ DEPENDENCIES
   remotipart (= 1.2.1)
   responders (= 2.2.0)
   roxml (= 3.1.6)
-  rspec-instafail (= 0.5.0)
   rspec-rails (= 3.4.2)
   rubocop (= 0.40.0)
   ruby-oembed (= 0.10.0)