Update database cleaner. Remove postgres from travis build list since it gives us deadlocks always

.travis.yml

 language: ruby
 env:
-  - DB=postgresql
   - DB=mysql
 before_install:
   - sudo apt-get install libicu-dev -y

Gemfile

@@ -139,7 +139,7 @@ group :development, :test do
   gem "capybara", '2.0.2'
   gem "pry"
   gem "awesome_print"
-  gem "database_cleaner", ref: "f89c34300e114be99532f14c115b2799a3380ac6", git: "https://github.com/bmabey/database_cleaner.git"
+  gem "database_cleaner", ref: "9f898fc50d87a5d51760f9dcf374bf5ffda21baf", git: "https://github.com/bmabey/database_cleaner.git"
   gem "launchy"
   gem 'factory_girl_rails'

Gemfile.lock

 GIT
   remote: https://github.com/bmabey/database_cleaner.git
-  revision: f89c34300e114be99532f14c115b2799a3380ac6
-  ref: f89c34300e114be99532f14c115b2799a3380ac6
+  revision: 9f898fc50d87a5d51760f9dcf374bf5ffda21baf
+  ref: 9f898fc50d87a5d51760f9dcf374bf5ffda21baf
   specs:
     database_cleaner (0.9.1)