Remove rbx-2 from Travis CI build matrix

because it can no longher be installed due to missing binaries.

See: http://binaries.rubini.us/index.txt

Author: felixbuenemann

.travis.yml

@@ -45,7 +45,6 @@ rvm:
   - ree
 matrix:
   allow_failures:
-    - rvm: rbx-2
     - os: osx
   include:
     - rvm: 2.0.0
@@ -54,7 +53,5 @@ matrix:
       env: DB=mariadb10
     - rvm: 2.0.0
       env: DB=mysql57
-    - rvm: rbx-2
-      env: RBXOPT=-Xgc.honor_start=true
     - rvm: 2.0.0
       os: osx