Upgrade unicorn and unicorn-worker-killer.

Upgrade unicorn from 4.9.0 to 5.1.0 and unicorn-worker-killer from 0.4.2 to 0.4.4.

Changelog for unicorn: http://unicorn.bogomips.org/NEWS.html

Changelog for unicorn-worker-killer: https://github.com/kzk/unicorn-worker-killer/blob/bdec225f028d1bda01b5888578c479b0c705f1a8/ChangeLog

Gemfile

@@ -122,8 +122,8 @@ gem 'diffy', '~> 3.0.3'
 
 # Application server
 group :unicorn do
-  gem 'unicorn', '~> 4.9.0'
-  gem 'unicorn-worker-killer', '~> 0.4.2'
+  gem 'unicorn', '~> 5.1.0'
+  gem 'unicorn-worker-killer', '~> 0.4.4'
 end
 
 # State machine

Gemfile.lock

@@ -554,7 +554,7 @@ GEM
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rainbow (2.1.0)
-    raindrops (0.15.0)
+    raindrops (0.17.0)
     rake (10.5.0)
     rb-fsevent (0.9.6)
     rb-inotify (0.9.5)
@@ -760,9 +760,8 @@ GEM
       unf_ext
     unf_ext (0.0.7.2)
     unicode-display_width (1.1.1)
-    unicorn (4.9.0)
+    unicorn (5.1.0)
       kgio (~> 2.6)
-      rack
       raindrops (~> 0.7)
     unicorn-worker-killer (0.4.4)
       get_process_mem (~> 0)
@@ -981,8 +980,8 @@ DEPENDENCIES
   uglifier (~> 2.7.2)
   underscore-rails (~> 1.8.0)
   unf (~> 0.1.4)
-  unicorn (~> 4.9.0)
-  unicorn-worker-killer (~> 0.4.2)
+  unicorn (~> 5.1.0)
+  unicorn-worker-killer (~> 0.4.4)
   version_sorter (~> 2.1.0)
   virtus (~> 1.0.1)
   vmstat (~> 2.2)