try to make travis 2.9 work

Author: cowtowncoder

.travis.yml

@@ -1,8 +1,7 @@
 language: java
 
-# Since Jackson 2.7, build requires jdk7, although module itself works on jdk6 still (for now)
+# JDK 7 no longer works, just use JDK 8
 jdk:
-  - openjdk7
   - openjdk8
 
 # Below this line is configuration for deploying to the Sonatype OSS repo