Include MiMa exclude as per build error instructions - this version incompatibility should be irrelevent, as it will only surface if a master is talking to a worker running a different version of spark.

Author: Nathan Kronenfeld

project/MimaExcludes.scala

@@ -53,6 +53,10 @@ object MimaExcludes {
               "org.apache.spark.mllib.linalg.Matrices.randn"),
             ProblemFilters.exclude[MissingMethodProblem](
               "org.apache.spark.mllib.linalg.Matrices.rand")
+          ) ++ Seq(
+            // SPARK-4772
+            ProblemFilters.exclude[IncompatibleResultTypeProblem](
+              "org.apache.spark.Accumulators.localAccums")
           )
 
         case v if v.startsWith("1.2") =>