OAK-8894: Build error on travis-ci

Use correct pgp key for MongoDB 3.2 server

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/branches/1.2@1873651 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/.travis.yml b/.travis.yml
index bbe29c4..c7dc494 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,10 +17,10 @@
 sudo: required
 # OAK-7120: Use specific MongoDB version on travis-ci
 before_install:
-  - "sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv EA312927"
+  - "wget -qO - https://www.mongodb.org/static/pgp/server-3.2.asc | sudo apt-key add -"
   - "echo 'deb http://repo.mongodb.org/apt/ubuntu trusty/mongodb-org/3.2 multiverse' | sudo tee /etc/apt/sources.list.d/mongodb-org-3.2.list"
   - "sudo apt-get update"
-  - "sudo apt-get install -y --allow-downgrades mongodb-org-server=3.2.18"
+  - "sudo apt-get install -y --allow-downgrades mongodb-org-server=3.2.22"
   - "sudo rm -r /var/lib/mongodb/journal"
   - "sudo rm -r /var/lib/mongodb/diagnostic.data"
   - "sudo rm /var/lib/mongodb/*"