upgrade Travis to use 2.12.0 (was RC2)

Author: SethTisue

.travis.yml

@@ -20,7 +20,7 @@ env:
     - TEST_COMMAND="scripted"
     - TEST_COMMAND="testFunctional"
     - TEST_COMMAND="-Dmima.testScalaVersion=2.11.8 testFunctional"
-    - TEST_COMMAND="-Dmima.testScalaVersion=2.12.0-RC2 testFunctional"
+    - TEST_COMMAND="-Dmima.testScalaVersion=2.12.0 testFunctional"
 
 script:
   - sbt $TEST_COMMAND