Fix the name of a flag in an error message

The name of the flag was camelCased whereas the correct name
is underscore separated.

PiperOrigin-RevId: 160245462
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
index da3430a..a7fc147 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
@@ -66,7 +66,8 @@
         throw new EvalException(
             getLocation(),
             "First argument of 'load' must be a label and start with either '//' or ':'. "
-                + "Use --incompatibleLoadArgumentIsLabel=false to temporarily disable this check.");
+                + "Use --incompatible_load_argument_is_label=false to temporarily disable this "
+                + "check.");
       }
     }