fix travis issues and run build against ruby 1.9.3

.travis.yml

 env:
   - DB=mysql
   - DB=sqlite
-before_install: sudo apt-get install libicu-dev -y
+before_install:
+  - sudo apt-get install libicu-dev -y
+  - echo "yes" | gem uninstall json ffi
 branches:
   only:
     - 'master'
 rvm:
   - 1.9.2
+  - 1.9.3
 before_script:
   - "cp config/database.yml.$DB config/database.yml"
   - "cp config/gitlab.yml.example config/gitlab.yml"