Fixing issue where OpenJDK PPA would not install in Ubuntu Trusty in packaging tests.

* Reinstalled certificates in Ubuntu trusty upon provisioning in order to fix an issue where the OpenJDK PPA could not be installed.
* Updated RBT to lastest version 0.7.11

Reviewed at https://reviews.apache.org/r/66482/
diff --git a/rbt b/rbt
index 5b94e53..7531fcb 100755
--- a/rbt
+++ b/rbt
@@ -16,7 +16,7 @@
 set -e
 
 HERE=$(cd `dirname "${BASH_SOURCE[0]}"` && pwd)
-RBTOOLS_VERSION=0.7.5
+RBTOOLS_VERSION=0.7.11
 if ! [ -f "$HERE/build-support/rbt.venv/BOOTSTRAPPED" ] || \
     [ x`cat "$HERE/build-support/rbt.venv/BOOTSTRAPPED"` != x$RBTOOLS_VERSION ]; then
 
diff --git a/test/deb/ubuntu-trusty/provision.sh b/test/deb/ubuntu-trusty/provision.sh
index 2d886bf..1a62288 100644
--- a/test/deb/ubuntu-trusty/provision.sh
+++ b/test/deb/ubuntu-trusty/provision.sh
@@ -1,5 +1,6 @@
 #!/bin/bash
 
+apt-get install --reinstall ca-certificates
 add-apt-repository ppa:openjdk-r/ppa -y
 apt-get update
 apt-get install -y openjdk-8-jre zookeeperd