[SPARK-7681] [MLLIB] remove mima excludes for 1.3

There excludes are unnecessary for 1.3 because the changes were made in 1.4.x.

Author: Xiangrui Meng <meng@databricks.com>

Closes #6254 from mengxr/SPARK-7681-mima and squashes the following commits:

7f0cea0 [Xiangrui Meng] remove mima excludes for 1.3

project/MimaExcludes.scala

@@ -187,14 +187,7 @@ object MimaExcludes {
             ProblemFilters.exclude[MissingMethodProblem](
               "org.apache.spark.mllib.linalg.Matrix.isTransposed"),
             ProblemFilters.exclude[MissingMethodProblem](
-              "org.apache.spark.mllib.linalg.Matrix.foreachActive"),
-            // SPARK-7681 add SparseVector support for gemv
-            ProblemFilters.exclude[MissingMethodProblem](
-              "org.apache.spark.mllib.linalg.Matrix.multiply"),
-            ProblemFilters.exclude[MissingMethodProblem](
-              "org.apache.spark.mllib.linalg.DenseMatrix.multiply"),
-            ProblemFilters.exclude[MissingMethodProblem](
-              "org.apache.spark.mllib.linalg.SparseMatrix.multiply")
+              "org.apache.spark.mllib.linalg.Matrix.foreachActive")
           ) ++ Seq(
             // SPARK-5540
             ProblemFilters.exclude[MissingMethodProblem](