Skylark no longer crashes when the default value of an attribute is a label string that points to a remote repository.

Fixes #1442.

--
MOS_MIGRATED_REVID=132320130
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 ea52e11..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
@@ -172,7 +172,7 @@
             new SkylarkComputedDefaultTemplate(
                 type, callback.getParameterNames(), callback, ast.getLocation()));
       } else {
-        builder.defaultValue(defaultValue);
+        builder.defaultValue(defaultValue, env.getGlobals().label());
       }
     }