Fixing compilation in Scala 2.11

Author: Alexey Kudinkin

hudi-client/hudi-spark-client/src/main/scala/org/apache/hudi/HoodieConversionUtils.scala

@@ -26,11 +26,14 @@ import scala.collection.JavaConverters
 object HoodieConversionUtils {
 
   /**
-   * Converts Java's [[ju.Map]] into Scala's (immutable) [[Map]] (by defautl [[JavaConverters]] convert to
+   * Converts Java's [[ju.Map]] into Scala's (immutable) [[Map]] (by default [[JavaConverters]] convert to
    * a mutable one)
    */
-  def mapAsScalaImmutableMap[K, V](map: ju.Map[K, V]): Map[K, V] =
-    JavaConverters.mapAsScalaMap(map).toMap
+  def mapAsScalaImmutableMap[K, V](map: ju.Map[K, V]): Map[K, V] = {
+    // NOTE: We have to use deprecated [[JavaConversions]] to stay compatible w/ Scala 2.11
+    import scala.collection.JavaConversions.mapAsScalaMap
+    map.toMap
+  }
 
   def toJavaOption[T](opt: Option[T]): org.apache.hudi.common.util.Option[T] =
     if (opt.isDefined) org.apache.hudi.common.util.Option.of(opt.get) else org.apache.hudi.common.util.Option.empty()