Initialize projection used for Python UDF

>>> from pyspark.sql.functions import udf, rand
>>> spark.range(10).select(udf(lambda x: x)(rand())).show()

java.lang.NullPointerException
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$SpecificMutableProjection.apply(Unknown Source)
	at org.apache.spark.sql.execution.python.EvalPythonExec.$anonfun$doExecute$10(EvalPythonExec.scala:126)
	at scala.collection.Iterator$$anon$10.next(Iterator.scala:461)
	at scala.collection.Iterator$$anon$10.next(Iterator.scala:461)
	at scala.collection.Iterator$GroupedIterator.takeDestructively(Iterator.scala:1161)
	at scala.collection.Iterator$GroupedIterator.go(Iterator.scala:1176)
	at scala.collection.Iterator$GroupedIterator.fill(Iterator.scala:1213)