[SPARK-14952][CORE][ML] Remove methods that were deprecated in 1.6.0

#### What changes were proposed in this pull request?

This PR removes three methods the were deprecated in 1.6.0:
- `PortableDataStream.close()`
- `LinearRegression.weights`
- `LogisticRegression.weights`

The rationale for doing this is that the impact is small and that Spark 2.0 is a major release.

#### How was this patch tested?
Compilation succeded.

Author: Herman van Hovell <hvanhovell@questtec.nl>

Closes #12732 from hvanhovell/SPARK-14952.

2 files changed, 0 insertions, 19 deletions

diff --git a/python/pyspark/ml/classification.py b/python/pyspark/ml/classification.py
index cc562d2d3d..f616c7fbec 100644
--- a/python/pyspark/ml/classification.py
+++ b/python/pyspark/ml/classification.py
@@ -214,16 +214,6 @@ class LogisticRegressionModel(JavaModel, JavaMLWritable, JavaMLReadable):
     """
 
     @property
-    @since("1.4.0")
-    def weights(self):
-        """
-        Model weights.
-        """
-
-        warnings.warn("weights is deprecated. Use coefficients instead.")
-        return self._call_java("weights")
-
-    @property
     @since("1.6.0")
     def coefficients(self):
         """
diff --git a/python/pyspark/ml/regression.py b/python/pyspark/ml/regression.py
index 8e76070e9a..d490953f79 100644
--- a/python/pyspark/ml/regression.py
+++ b/python/pyspark/ml/regression.py
@@ -129,15 +129,6 @@ class LinearRegressionModel(JavaModel, JavaMLWritable, JavaMLReadable):
     """
 
     @property
-    @since("1.4.0")
-    def weights(self):
-        """
-        Model weights.
-        """
-        warnings.warn("weights is deprecated. Use coefficients instead.")
-        return self._call_java("weights")
-
-    @property
     @since("1.6.0")
     def coefficients(self):
         """