Update doc

Author: sryza

docs/building-spark.md

@@ -113,9 +113,9 @@ mvn -Pyarn -Phive -Phive-thriftserver-0.12.0 -Phadoop-2.4 -Dhadoop.version=2.4.0
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 # Building for Scala 2.11
-To produce a Spark package compiled with Scala 2.11, use the `-Pscala-2.11` profile:
+To produce a Spark package compiled with Scala 2.11, use the `-Dscala-2.11` property:
 
-    mvn -Pyarn -Phadoop-2.4 -Pscala-2.11 -DskipTests clean package
+    mvn -Pyarn -Phadoop-2.4 -Dscala-2.11 -DskipTests clean package
 
 Scala 2.11 support in Spark is experimental and does not support a few features.
 Specifically, Spark's external Kafka library and JDBC component are not yet