Update freebsd-12 base image

As freebsd-12 is currently the development version of freebsd,
keeping the base image in sync with the binary packages we
install is essential.

Change-Id: Idf53d3f5865382068704ec26170ad2c4f749c856
diff --git a/gce/vm.sh b/gce/vm.sh
index 3b0ebd5..eaeb390 100755
--- a/gce/vm.sh
+++ b/gce/vm.sh
@@ -54,7 +54,7 @@
     "ubuntu-docker-slave-1 https://www.googleapis.com/compute/v1/projects/ubuntu-os-cloud/global/images/ubuntu-1510-wily-v20151026 ubuntu_15.10-x86_64-docker-1 europe-west1-d default startup-script=jenkins-slave.sh ubuntu-15-10-slave.sh ubuntu-15-10-docker.sh bootstrap-bazel.sh linux-android.sh cleanup-install.sh"
     "ubuntu-docker-slave-2 https://www.googleapis.com/compute/v1/projects/ubuntu-os-cloud/global/images/ubuntu-1510-wily-v20151026 ubuntu_15.10-x86_64-docker-2 europe-west1-d default startup-script=jenkins-slave.sh ubuntu-15-10-slave.sh ubuntu-15-10-docker.sh bootstrap-bazel.sh linux-android.sh cleanup-install.sh"
     "freebsd-11-slave https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-11-0-stable-amd64-2017-01-06 freebsd-11-1 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
-    "freebsd-12-slave https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-06-02 freebsd-12-1 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
+    "freebsd-12-slave https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-07-04 freebsd-12-1 europe-west1-d default startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
     # Fow Windows, we use a custom image with pre-installed MSVC.
     "windows-slave-1 windows-server-2012-r2-dc-v20160112-vs2015-cpp-python-msys windows-x86_64-1 europe-west1-d default windows-startup-script-ps1=jenkins-slave-windows.ps1"
     "windows-slave-2 windows-server-2012-r2-dc-v20160112-vs2015-cpp-python-msys windows-x86_64-2 europe-west1-d default windows-startup-script-ps1=jenkins-slave-windows.ps1"
@@ -90,7 +90,7 @@
     "ubuntu-16-04-slave-staging ubuntu-1604-lts ubuntu_16.04-x86_64-staging europe-west1-d staging startup-script=jenkins-slave.sh ubuntu-16-04-slave.sh bootstrap-bazel.sh linux-android.sh cleanup-install.sh"
     "ubuntu-docker-slave-staging https://www.googleapis.com/compute/v1/projects/ubuntu-os-cloud/global/images/ubuntu-1510-wily-v20151026 ubuntu_15.10-x86_64-docker-staging europe-west1-d staging startup-script=jenkins-slave.sh ubuntu-15-10-slave.sh ubuntu-15-10-docker.sh bootstrap-bazel.sh linux-android.sh cleanup-install.sh"
     "freebsd-11-slave-staging https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-11-0-stable-amd64-2017-01-06 freebsd-11-staging europe-west1-d staging startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
-    "freebsd-12-slave-staging https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-06-02 freebsd-12-staging europe-west1-d staging startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
+    "freebsd-12-slave-staging https://www.googleapis.com/compute/v1/projects/freebsd-org-cloud-dev/global/images/freebsd-12-0-current-amd64-2017-07-04 freebsd-12-staging europe-west1-d staging startup-script=jenkins-slave.sh freebsd-slave.sh freebsd-ci-homedir.sh"
     # Fow Windows, we use a custom image with pre-installed MSVC.
     "windows-slave-staging windows-server-2012-r2-dc-v20160112-vs2015-cpp-python-msys windows-x86_64-staging europe-west1-d staging windows-startup-script-ps1=jenkins-slave-windows.ps1"
     "windows-msvc-slave-staging windows-server-2012-r2-dc-v20160112-vs2015-cpp-python-msys windows-msvc-x86_64-staging europe-west1-d staging windows-startup-script-ps1=jenkins-slave-windows-msvc.ps1"