Travis-CI: Use OpenJDK instead

The new license for Oracle JDK downloads seem something worthy
of avoidance. Also avoid OpenJDK 8 because it's missing some
crypto algorithms we need for tests if it's before b180 or so.

Author: kruton

.travis.yml

@@ -1,12 +1,11 @@
 language: java
 jdk:
-  - oraclejdk9
-  - oraclejdk8
+  - openjdk9
+  - openjdk11
 addons:
   apt:
     packages:
       - docker-ce
-      - oracle-java8-installer
 services:
   - docker
 cache:

gradle.properties

@@ -25,5 +25,5 @@ description=SSH library used in the ConnectBot app
 bintrayUser=dummyUser
 bintrayApiKey=dummyApiKey
 
-officialJdk=oraclejdk9
+officialJdk=openjdk9
 gitHubUrl=https\://github.com/connectbot/sshlib