Rollback of commit 4381a1d6e8f711957f430aac0c301acec6dfa0eb.

*** Reason for rollback ***

Breaks all projects using Bazel, see https://ci.bazel.io

*** Original change description ***

Deprecated and removed HOST_CFG and DATA_CFG global variables.

--
MOS_MIGRATED_REVID=133005398
diff --git a/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java b/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java
index 078ab2d..2e4bbb6 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java
@@ -259,7 +259,10 @@
 
     if (containsNonNoneKey(arguments, CONFIGURATION_ARG)) {
       Object trans = arguments.get(CONFIGURATION_ARG);
-      if (trans.equals("data")) {
+      if (trans instanceof ConfigurationTransition) {
+        // TODO(laurentlb): Deprecated, to be removed in August 2016.
+        builder.cfg((ConfigurationTransition) trans);
+      } else if (trans.equals("data")) {
         builder.cfg(ConfigurationTransition.DATA);
       } else if (trans.equals("host")) {
         builder.cfg(ConfigurationTransition.HOST);