Update travis-ci to test against oraclejdk8. openjdk8 is not supported yet,...

Update travis-ci to test against oraclejdk8. openjdk8 is not supported yet, apparently (but should still work w/Floodlight).

.travis.yml

@@ -3,8 +3,8 @@
 language: java
 
 jdk:
- - oraclejdk7
- - openjdk7
+ - oraclejdk8
+# - openjdk8 does not appear to be an option as of 04/29/16
 
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