Revert 0b621da86aa5b4e63e2cf7104f1ea7e24050747c (#165)

Re-enable FreeBSD in the Jenkins config.
diff --git a/jenkins/BUILD b/jenkins/BUILD
index 7138172..5628011 100644
--- a/jenkins/BUILD
+++ b/jenkins/BUILD
@@ -26,6 +26,12 @@
 DARWIN_PREFIX = "darwin-x86_64"
 DARWIN_COUNT = 8
 
+FREEBSD_11_PREFIX = "freebsd-11"
+FREEBSD_11_COUNT = 2
+
+FREEBSD_12_PREFIX = "freebsd-12"
+FREEBSD_12_COUNT = 2
+
 UBUNTU_1404_PREFIX = "ubuntu_14.04-x86_64"
 UBUNTU_1404_COUNT = 4
 
@@ -76,6 +82,18 @@
     labels = ["no-release"],
 )
 
+jenkins_nodes(
+    FREEBSD_11_PREFIX,
+    FREEBSD_11_COUNT,
+    labels = ["no-release"],
+)
+
+jenkins_nodes(
+    FREEBSD_12_PREFIX,
+    FREEBSD_12_COUNT,
+    labels = ["no-release"],
+)
+
 #
 # A deploy slave used for release work and syncing
 # our repositories.
@@ -241,6 +259,8 @@
                   ":jenkins-common-configs",
                   ":config/org.jenkinsci.plugins.ghprb.GhprbTrigger.xml",
               ] + jenkins_node_names(DARWIN_PREFIX, DARWIN_COUNT) +
+              jenkins_node_names(FREEBSD_11_PREFIX, FREEBSD_11_COUNT) +
+              jenkins_node_names(FREEBSD_12_PREFIX, FREEBSD_12_COUNT) +
               jenkins_node_names(WINDOWS_PREFIX, WINDOWS_COUNT) +
               jenkins_node_names(UBUNTU_DOCKER_PREFIX, UBUNTU_DOCKER_COUNT) +
               jenkins_node_names(UBUNTU_1404_PREFIX, UBUNTU_1404_COUNT) +
@@ -262,6 +282,8 @@
         ":config_xml",
         ":darwin-x86_64-staging",
         ":deploy-staging",
+        ":freebsd-11-staging",
+        ":freebsd-12-staging",
         ":jenkins-common-configs",
         ":ubuntu_14.04-x86_64-staging",
         ":ubuntu_16.04-x86_64-docker-staging",